CONG XGHE SEVH HOC & BAO Xt THI''''C \ ^ 1 T NGHIExN c u t ; TEVH HL^OXG TREN CAY LUA (Oi^za sativa L ) GS TS Bui Chf BiJu Vien tnicfng Vien KHKTNN Mien Nam Nhufng thach thiJfc cho an n inh lu''''ang thirc[.]
Trang 1CONG XGHE SEVH HOC & BAO Xt THI'C \ ^ 1 T
NGHIExN c u t ; TEVH HL^OXG TREN CAY LUA (Oi^za sativa L.)
GS TS Bui Chf BiJu
Vien tnicfng Vien KHKTNN Mien Nam
Nhufng t h a c h thiJfc cho an n i n h lu'ang thirc toan the gidi va Viet N a m t a p trung
vao cac sU k i e n nhiT sau: (i) sii t h a y ddi khi hau toan cau l a m a m len k h i quyen t r a i dat, (ii) thieu nudfc tudi cho cay trong, (iii) nguy ca thieu hijt lu'ang thiic trUdc t i n h
t r a n g dat nong nghiep giam va dan sd tang, (iv) stress phi sinh hoc ngay cang bieu
h i e n nghiem trong, dac biet kho h a n Ben canh do, sau b e n h hai ngay cang p h a t
t r i e n do each thufc ufng xuf cua con ngUai trong nong nghiep t h a m canh theo xu hUdng
k e m ben vufng, can b a n g sinh hoc t r e n dong rugng bi pha va Co nai tinh he thong trong nong nghiep k h o n g con nufa Tfng dung cong nghe sinh hoc ket hgp vdi phuang
p h a p truyen thong dang la giai p h a p dugc khuyen khich Trong bai nay, chung toi chi t a p t r u n g vao hai ddi tirgng chinh la ray nau va benh dao on t r e n cay lua
I THANH T l / U CUA KHOA HOC CAY TRONG
Trong Dai Hgi Qudc te ve Khoa hgc Cay trong lan thuf n a m tai H a n Qud^c, Giao sir J e r r y Nelson (2008) thugc DH Missouri, Hoa Ky da bat dau vdi bai p h a t bieu quan t r g n g ve "Khoa hoc cay trdng va sg dap ufng nhu cau cho tUOng lai" Sg phat trien cua Trung Qud^c va An Do nhiT quo'c gia day tiem n a n g ve kinh te da lam thay ddi quan diem toan cau, tir "giup da" sang "canh tranh" Nong nghiep va khoa hgc cay trdng tuy dat nhieu t h a n h tgu rgc rd, vdi sg dau tiT ngay cang nhieu cua td chufc tir n h a n tai cac nirdc dang p h a t trien; nhimg nong dan cd the se ddi dien gay gat vdi quyen sd hflu tri tue, quyen tac gia Khoa hgc cay trdng khong the dufng rieng mgt minh ma dang xem xet can t h a n cac yeu td^ kinh te, xa hgi, moi tnrdng, chinh tri, trong dd bao gdm thi tru'dng n a n g lugng sinh hgc, thirang mai hda toan cau, chung
t a se phai n h a n m a n h dac biet ve chat lugng va sg an toan luong thgc, thgc pham nhieu han so vdi yeu td^ moi tru'dng va xa hgi San xuat lUOng thgc se khong dap ufng nhu cau trong tirang lai; nhir vay chung ta phai xem xet lai "moi tnfdng" mgt each cdi
md han, n h a n m a n h den p h a n tich cac t i n h t r a n g cd tinh chat t a n g t h e m gia tri (added-value traits) ddi vdi chat lu'gng sdng cua con ngirdi (Nelson 2008)
Lua nirdc trdi chie^m hem 50% dien tich canh tac t r e n the gidi, nhimg s a n lirgng thdc ehi ddng gdp k h o a n g 25%; day la vung san xuat lua cua n h ^ n g ngu'di ngheo
n h a t the gidi, day rui ro do lu lgt, h a n h a n , xam n h a p man Tiem n a n g ve n a n g suat d day cdn cd t h e k h a i t h a c t h e m so vdi n a n g suat da dgi t r a n d viing lua nUde tudi Giai p h a p ve cay lua C4 d a n g la phirang hirdng dang du'gc thgc h i e n trong chien lugc lau dai k e t h g p vdi t h a n h tgu trong khai thac lAi the lai F l Ngirdi ta
d a n g p h a t t r i e n cay lua C3 sang cay C4 theo mo h i n h GECROS do Yin va Struik
de xuat tCr n a m 2008 (Zeigler 2008) Hien nay, Bill and Melinda Gate Foundation
da t a i trg cho IRRI thgc h i e n tao r a gio'ng lua C4, giai doan 2009 - 2012
•:• HQI NGHI KHO.-V HQC CONG NGHE TO.\N QUOC VE BVTV LAN THL' 3 •>
- _
Trang 2Giao Slf Ronald Phillips thugc DH Minnesota, Hoa K}', ngu'di \iia dgoc giai thu'dng
International Food Prize 2007, da cd mgt tdng quan rat d a n g chu y ve cong nghe sinh hgc trong cay trdng Trudc tinh hinh dan sd t a n g binh quan 1 ty ngu'di trong
14 n a m , va dien tich nong nghiep chi cdn 1,5 ti ha trong n a m 2050; s a n lu'gng Ido'ng thgc toan cau se phai t a n g gap doi so vdi hien nay Giai phap nao? Viec giai ma bg gen cay mo h i n h cd the giup ich gi cho cai tie'n gidng cay trdng (bao gom cay lua) Cay mo hinh Arabidopsis thaliana da dirge sii dgng eho nhieu loai eay k h a c thain khao Tuang tg, eay mo hinh Braehydopium dugc ufng dung cho m§ cdc vung on ddi, cay Lotus japonicus la mo h i n h cd dinh dam, Medicargo truncatula la mo h m h cho cay hg Dau, lua Oryza sativa la mo hinh sinh hgc eho me cdc, cay Populus dufgc ufng dgng de nghien cufu sinh hgc va di truyen cua gio'ng cay riTng Nhieu y tifang m a i da thgc sg trd t h a n h hien thgc nhd thi nghiem t r e n cay mo hinh Thi dg: t i n h k h a n g tuyen trung gay benh sUng re nhd p h a n tuf RNA can thiep ufng dgng t r e n cay Arabidopsis, san xua't vaccine dich ta t r e n eay lua, va cay bap cd gen "eolicinogenic
Bg gen vd cung phufc tap cua cay bap da gan nhU dugc giai ma hoan toan, do dd, bay gid ngu'di ta cd the xem nd nhU cay mo hinh vao cudi n a m 2009 (Phillip 2008)
Cf Trung Qudc, Giao Su QiFa Zhang thugc DH Ndng Nghiep Huazhong, cijng vdi cac ddng nghiep dang thgc hien chuong trinh qudc gia k h a ndi tieng, dd la phat trien giong lua "Green Super Rice" Thach thufc toan cau tnrdc sg kien t h a m canh lua la (i) sg p h a t trien sau benh hai quyet liet han + suf dgng thudc khdng dung, (ii) ap lgc t a n g n a n g sua't + bdn phan khdng dung, (iii) thieu nirdc tudi nghiem trgng, (iv) da't t h a m canh khdng cdn md rgng dirge nufa Ba muc tieu rd rang eua Green Super Riee la: giam dau vao, tang san lugng, moi trUdng td't Gid'ng lua theo chien lirgc nay la: k h a n g nhieu sau benh hai, hieu qua suf dung phan N cao, k h a n g han Gen dap img yeu cau hieu qua ha'p thu dinh dudng cao da dugc cdng bd: Gen dieu khien NUE (N uptake efficiency) dugc khai thac tir ngan hang gen (vdi 64.000 mau gidng lua cd truyen) + thir vien cac ddng mutants de tim Idem gen cho NUE, bao gdm 270.000 transformants dgc lap, va 20.000 flanking sequences trong thir vien T-DNA (Zhang 2008)
Cac n h a khoa hgc quan sat sg the h i e n gen O s P T F l dieu k h i e n hieu qua h a p thu lan, dinh vi t r e n n h i i m sac the so' 6 P h a t h i e n sg dap ufng r a t sdm vdi N b a n g
ky t h u a t microarray Hieu qua suf dgng p h a n d a m da giam n g h i e m t r g n g t r e n nhieu vung trdng lua Nghien cufu xu hudng n a n g sua't lua N giam d a n (dg a n yield declin-ing) ciia Cassman va ctv 1996 va tai lieu eua Li 1991, cho tha'y d Philippines, de
s a n xua't duge 1kg thdc, can bdn 15 - 18kg N, d Trung Qudc la 15 - 20kg N t r o n g giai doan 1958 - 1963, nhung giam xudng 9,1 kg N d giai doan 1981 - 1983, va h i e n nay la 5,0kg N (Zhang 2008) Bao ve eay t r d n g t r e n quan diem t d n g h g p : dinh dudng cay trdng, di truyen tinh k h a n g eua eay chu, di t r u y e n gen dgc t i n h cua pathogen, mdi trUdng sinh thai nai cay t r d n g t a n g tru'dng Mdi quan he a y dugc k e t hgp trong mgt chuang trinh lua "green super" d Trung Qudc la m g t m a u mUc cho cac nudc trdng lua nhu Viet Nam, tap hgp dugc nhieu n h a khoa hgc dau n g a n h vdi mdt chuang t r i n h mang tinh qudc gia, qudc t e , da linh vUc K e t qua nhU sau:
NhUng gen "ammonium transporter" trong cay lua da duac p h a n l a p thuoc ho gen OsAMT " ' ' '
V HQI NGHI KHOA HQC CONG NGHE TOAN QLOC VE BVTV LAN THLf 3 •>
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Trang 3Gen ddng hoa ammonium bao gdm glutamine synthetase (GSI, GS2), glutamate
s y n t h a s e (NADH-GOGAT, Fd-GOGAT) va glutamate dehydrogenase (GDH)
Gen ed chdc n a n g "ammonium transport" va "ammonium transfer" bao gdm
a s p a r t a t e aminotransferase (AspAT) va asparagine s y n t h e t a s e (AS)
Gen dap Ung vdi yeu cau k h a n g h a n t r e n ca sd cho'ng chiu va t h o a t h a n cua cac quan the RILs, T-DNA m u t a n t library, trong dd IRAT109 dugc xem xet n h u ngudn cho gen k h a n g va cac DNA muc tieu dung trong chuyen n a p la CBF3, LOSS, S 0 S 2 , TPS, H V A l , N P K l , ZAT, NCRD3, N H X l , CodA (Zhang 2008)
Cac n h a khoa hgc da n g h i e n cUu gen dieu k h i e n "trehalose" la mgt diglucoside
k h d n g khuf, vCra cd chUc n a n g dg trU carbohydrate, vu'a cd chufc n a n g bao ve cay
t r d n g chd'ng lai stress Cay lua dugc k e t luan r a n g nd chd'ng ehiu vdi sg tdng hgp trehalose nhieu h a n nhUng cay t r d n g hai la m a m
Suha Jabaij (2008) thugc DH McGill, Canada, nghien cUu Id t r i n h cua gen ma hda enzyme thugc n h d m phenylpropanoid va isoflavones trong cay dau n a n h non; chUe n a n g cua chung dd'i vdi n a m h a i Rhizoctonia solani He thd'ng kich k h a n g (SAR) dugc quan t a m dac biet Hoat ddng cua Np-R lam t h a y ddi t h a n h te bao giup
re cay bao ve chd'ng lai Rhizoctonia Hoat dgng np-BNR l a m giam sg xam n h i i m eua pathogen d t r e n la cay dau va cay bdng vai Cac enzyme thugc nhdm isoflavones r a t quan t r g n g trong ca che de n e n sg p h a t t r i e n cua b e n h nhd np-BNR Rouf Mian (2008) thugc USDA-ARS, va DH Ohio, Hoa Ky nghien cufu tinh khang cua dau tuong ddi vdi ray m e m (Aphis glycines) Ray mem lam m a t 50% n a n g sua't dau tuang tai Minnesota, la ngudn vecta truyen benh sieu vi trung SMV, SDV, va AMV Tinh k h a n g aphid dugc kiem soat bdi gen chu lgc Cd 2 gen chinh dang dugc thgc hien ban dd di truyen Gidng dau n a n h PI243540, PI567301B va PI567324 duge ghi n h a n la gid'ng k h a n g aphid, vdi ea che antibiosis thugc ve PI243540 va ca che antixenosis thugc ve PI567301B va PI567324 Hai gen Rag va Rag 1 cua gidng Dawling va Jackson, theo thU tg da duge p h a n lap Gen Rag2 dugc p h a n lap tren PI243540 t r e n nhdm lien k e t F, dinh vi gida hai marker ke can la Satt34 va Set_033 Myoung Rae Cho va ctv (2008) thugc chuang t r i n h UMB, Malaysia, n g h i e n cufu
ve tac hai eua tuye'n t r u n g t r e n cay t r d n g d vung Ddng N a m A, bao gdm Viet Najn Tuyen t r u n g gay t h i e t h a i trung b i n h 12% san lugng cay trdng, bie'n t h i e n 3-21% Chung cd k h o a n g 200 loai t a n cdng t r e n 2.000 loai cay trdng Trong dd dang ke nha't la tuye'n t r u n g gay b e n h sUng re (Meloidogyne) t r e n hau h e t eay trdng can Tie'n bg mdi nha't la suf dung RNAi t r o n g gid'ng k h a n g tuyen trung, tai lieu duge cdng bd' t r e n PNAS 103 (39) cua Huang va ctv 2006 Ky t h u a t t h a n h lgc cay gd'c ghep dugc dng dgng phd bien t r e n eay hoa hdng Ky t h u a t luan canh vdi cay bdng van thg, eay dien t h a n h t h a n s a n (Sesbania rostrata), bdn p h a n hUu ca, phun thud'c, da dugc de cap N h d m tac gia nay edn p h a n lap dugc dd'i tUgng gay h a i t r e n tCmg cay t r d n g n h u lua, chudi, cay vai, dda d Malaysia va Viet Nam
•:• HQI NGHI KHOA HQC CONG NGHE TOAN QUOC VE BVTV LAN THL' 3 •
33"
Trang 4li Dl TRUYEN PHAN TLT TRONG BAO VE CAY LUA (Oryza sativa L.)
2.1 u n g d u n g c o n g n g h $ s i n h h o c va t i n s i n h h o c
Ban do gen eay lua da dugc giai ma t h a n h cong Trinh tg DNA cha't I f ^^^^ ^^° cua genome cay lua chiem 95%, vdi do ldn p h a n tuf 389 Mb, phu t r e n t a t ca ca^^^^
n h i l m va 2 t a m dgng cua 12 n h i i m sac t h e Tong sd nguyen to chuyen vi hien ^ ^ ^ xac dinh la 37.544 nguyen td, chiing lien quan den cac gen m a h o a protein q trgng Cd k h o a n g 50% sd gen chUa bie't chUe nang
Mgt dg an hgp tac qudc te mdi, cd t i n h chat lich suf, danh dau sg p h a t ^^J^J^''^^^ nghe sinh hoe cay lua, dd la «Rice Annotation Project 1» (RAPl) tU n a m , gdm cac ngi dung: d a t ten va eho ky hieu thd'ng n h a t trong n g a n ^ ^ ' ^ ^ ^ J j j ^ ' ^ ^ ^ nghien edu genome hgc cd tinh chat so s a n h vdi genome khac, ufng dgng a n cua genome hgc chUc nang
Cac p h a n m e m chuyen dgng nhU Fgenesh, Gensean, Glocate, BlatRice d a n g dugc
khuyen khich s\i dung de tim kiem gen mgc tieu, sau giai doan giai ma gen cay^lua
t h a n h edng vang dgi Phuang phap tim kiem md gen mgc tieu (allele mining) cung dugc t a p trung khai thac locus mdi hoae alen mdi (Ebaka va Yano, Trung T a m nghien cUu tai nguyen genome cay lua, N h a t ) (http://www.rgrc.dna.affrc.go.jp) Mgt dg a n qud'e ndi tieng khac, dd la OMAP (Oryza Map Alignment Project) da duge trien khai kha t h a n h cong N h i i m sac the sd 3 cua cay lua dugc chgn l a m muc tieu xem xet dau tien va ed ket qua budc dau, vdi ket qua so s a n h gifla O sativa
va O nivara [Genome Research 15:1284 (2005)], so s a n h giUa lua va ngd [Plant Cell 17:343 (2005)]
Rod Wing (DH Arizona, USA) xem xet d mufc do chi t i e t h a n t r e n n h i i m sac t h e
sd 1, 3 va 10, n h a m xac dinh chdc n a n g cua gen trong genus Oryza bao gdm 2 loai Ida trdng va 22 loai hoang dai, dai dien cho 10 kieu genome k h a c nhau (http://www.OMAP.org) OMAP duge thUc hien t r e n ea sd 12 thU v i e n BAC chat lugng cao, dae t n m g cho 10 kieu genome cua Oryza Chuoi t r i n h tU "BAC end" cd
do ldn p h a n tuf 724 Mb thugc 10-12 t h u vien BAC da dugc suf d u n g vdi n g a n h a n g
du lieu "SnaPshot fingerprint" OMAP da cdng bd 5 b a n dd vat ly cua O nivara[AA],
0 rufipogon [AA], O glaberrima [AA], 0 punctata [BB], O b r a c h y a n t h a [FF] Viec sap xep t r i n h tg cua gen n a m t r e n dUdng t h a n g nhU vay se tao r a m g t a r r a y cUc ldn vdi each xep d a t gidng nhu genome cua Nipponbare, cung cap cho c h u n g t a h i n h
a n h kha hoan chinh ve sg tien hda cua genus Oryza K h a i t h a c cac gen k h a n g sau benh hai chinh td lua hoang k h a t h a n h cdng tU dau t h e ky 2 1 , n h d nhUng tie'n bg khoa hgc nhU vay
Ken McNally va ctv (2009, 2006), t h i e t ke r a n h d n g m a r k e r p h a n tuf mdi dUa
t r e n ea sd da h i n h tU mgt nucleotide b a n g dot bien diem (SNPs) cho genome cay lua SNPs ra't phd bien cho genome ngUdi, nhUng k h a h a n che t r o n g genome cay Ida Day cd the dugc xem nhu sg kien quan t r g n g t r o n g cdng nghe sinh hgc cay lua Cdng t r i n h nay la mdt hgp tac qudc te gida IRRI va Cdng ty Perlegen Sciences, Inc., thgc h i e n S N P cho ea genome bkng each chay sequencing cua nhieu gid'ng lua
•:• HQI NGHI KHOA HQC CONG NGHE TOAN QUOC VE BVTV LAN T H C 3 •>
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Trang 5k h a c nhau, thdng qua lai DNA-DNA t r e n array mUc do cao, vdi n h u n g nucleotides Ket qua r a t dang chu y vdi m a t do mdi S N P / 100 bp
T i n h k h a n g ben vUng, pho k h a n g rgng ddi vdi b e n h h a i la ndi dung quan trgng Tuy n h i e n , cho de'n nay ca che t i n h k h a n g va Id t r i n h h o a t ddng eua gen sd lugng van chUa duge biet rd T h d n g thudng, dd la n h d n g gen dap ufng lai co che tg bao
ve cua cay, thi du n h u oxalate oxidase, chitinase, P R I , v.v Cdn lai n h d n g gen
k h a c v a n ehUa dugc bie't rd chUc n a n g cua chung
Cdng tac chgn tao gid'ng lua trong tUOng lai gid'ng nhU cdng viec theo ddi da'u vet
cua n h d n g doan p h a n td cUc nhd t r e n mdi n h i e m sic the cua quan the con lai dang
p h a n ly, rdi tien h a n h lga chgn cac t i n h t r a n g t r e n ea sd d a n h gia kieu gen nhd
m a r k e r p h a n td, kiem t r a lai kieu h i n h t r e n cac vung sinh t h a i khac nhau
Genomics cd tinh so s a n h la ngi dung quan t r g n g trong thdi gian qua va trong tuang lai vdi nhUng dng dgng cge ky n h a n h chdng eua nd Td edng trinh cua Moore
va ctv vao n a m 1995 de'n cdng t r i n h eua Paterson va ctv vao n a m 2004 cho tha'y: genome cay Ida khdng phai don gian, nd dugc xem la genome to tien cua cac m i cdc khac, vdi 62% transcriptome cd t i n h chat lap doan (duplicated) Lap doan d day bao gdm s g ' m a t gen va sg chuyen biet hda, thdng qua nghien cdu "Oxford Grid" Hudng
Uu tien cho n g a n h tin sinh hge [bioinformatics] dugc dac biet n h a n manh: (1) kha
n a n g p h a n biet gen vdi nhUng sequence khac; (2) so s a n h cac chudi t r i n h tg giUa cae loai vdi n g a n h a n g dU lieu ed sSn; (3) p h a n tich "datapoints" cd t i n h cha't phUe tap
va khd'i lugng cUc ky to ldn; (4) tim t h a y cac hgp p h a n cua gen (Phillip 2008)
2.2 G e n o m e h o c trong t i n h k h a n g ray n a u
Ray nau (Nilaparvata lugens) la dd'i tUgng gay h a i lua r a t nghiem trgng d Ddng
b a n g sdng Cdu Long Hien ed 18 gen da duge p h a n lap, cd 10 gen trgi va 8 gen lan Gen lan bph2 lien ke't vdi B p h l , va bph4 lien ke't vdi Bph3 (Yang va ctv 2004) Cac gen chu lUe dinh vi t r e n cac n h i i m sac the da dugc ghi n h a n n h u sau:
- N h i i m sic the 12: B p h l , bph2, Bph9, BphlO
- N h i i m sac the 4: Bph3, b p h l 2 , B p h l 4
- N h i i m sdc the 6: bph4
- N h i e m sac the 11: Bph6
- N h i i m sac the 3: b p h l l , B p h l 3 , B p h l 5
- N h i i m sac the 12: B p h l 8
Hai gen k h a n g r a y nau B p h l va BphlO dugc tim t h a y lien k e t r a t chat che vdi
R F L P m a r k e r , C185 va RG457 t r e n n h i i m sac the sd 12 (Jena va ctv 1991, Ishh
va ctv 1994, Hirabayashi va Ogawa 1996, Lang va Bdu 2003) Quan the lua hoang Oryza australiensis dugc p h a t h i e n cd m a n g gen Bph-10 va Bph-18
Tuy n h i e n , t i n h k h a n g ray nau cua eay Ida duge dieu k h i e n bdi n h d n g gen dan
n h u vay thUdng khdng ben vdng (Xu va ctv 2002) Sg p h a vd t i n h k h a n g ray nau cua gidng lua m a n g gen Bph-1 va bph-2 trong s a n xua't lua dugc ghi n h a n Cung
HQI NGHI KHOA HQC CONG NGHE TOAN QUOC VE BVTV LAN THL' 3 '>
35
Trang 6trong mgt ngudn vat lieu cho gen k h a n g ray nau, ngUai t a ed t h e xac dinh gi'\^, •
r a t ldn cua t i n h k h a n g sd lugng, nhung hieu biet ve linh^ vUc n a y v a n con nhieiJ
h a n che, bdi vi t i n h chat di truyen eua nhu'ng gen thd ye'u r a t khd k h a i thac, va ddi hdi nghien cdu phdc tap han r a t nhieu
Ngudn gen k h a n g r a y nau tU Ida hoang da dugc khai t h a c t h a n h cong la:
- Oryza australiensis: BphlO, B p h l 8
- Oryza officinahs: b p h l l , b p h l 2 , B p h l 3 , Bphl4, B p h l 5
- Oryza latifolia: B p h l 2
Hien cd 4 loai h i n h sinh hoc da duoc cong bd: B P H l va BPH2 cd d Dong N a m
A, BPH3 cd d trong IRRI lab do Saxena dinh danh, BPH4 chi dugc ghi n h a n a N a m
A (An Do, Bangladesh) Tuy nhien, the gidi da thay ddi quan diem biotype b a n g quan the ray liau, va thay ddi t h u a t ngU thay ddi dgc tinh ray nau b a n g t h u a t ngd thich nghi (fitness)
d ddng bang song Cdu Long (DBSCL), Ida hoang da dugc khai t h a c vdi 7 gen khang Dd la gen BphlO cua Oryza australiensis; b p h l l , b p h l 2 , B p h l 3 , B p h l 4 ,
B p h l 5 cua O officinalis; B p h l 2 eda 0 latifolia Mgt gen mdi dugc p h a n lap t r e n O
austrahensis la B p h l 2 dinh v\ tren vai dai eua nhiem sac the sd 12, n h u n g k h d n g
h e n ket vdi gen BphlO (gen da dugc Vien Lda ddng hda vao nam 2005) (Bdu va L a n g
2005, Lang va ctv 2008, 2007) Tuy chdng ta dang pha'n dau da dang ngudn di truyen tinh k h a n g ray nau; nhUng nd mdi ehi phat huy d mdc do nghien cdu; thUc
te san xua't cho tha'y, gidng chu lUe d DBSCL cd ngudn gdc k h a n g td ngudn v a t lieu
r a t dan dieu: ehu ye'u tU CR94-13 va Babawee Vdi gen lan dieu khien t i n h k h a n g , chdng ta phai luu y nhieu han de'n tinh ddng hgp td trong khuye'n cao sd dgng h a t gid'ng xac n h a n Ngan h a n g gen Ida Viet Nam cung r a t thieu ngudn cung cap gio'ng khang Quan the Ida hoang chu'a dugc nghien cdu, nhung ra't trien vgng de khau t h a c
Sg pha vd tinh k h a n g ray nau eua cac gidng Ida hien nay do sg kien thich nghi cua ray (sinh vat bac cao, chi can 2 vdng ddi tap giao, m a t khoang 60 ngay, r a y cd the tao ra quan the mdi thich nghi vdi cay chu; neu ap lUc quan the r a y qua cao
t r e n ddng rugng)
Sg ddng gdp tuang ddi cua con lai dd'i vdi the he ke tiep la "fitness" (thich nghi) Chgn lgc dat ket qua td't lam thay ddi t a n sua't kieu gen trong con lai, dieu dd can mgt thay ddi ve t a n suat gen trong giao td eua quan the bd me Chgn lgc trong quan the bd me ed the dugc thgc hien d mdc do kieu hinh hon la d mdc do giao td l a m
p h a t sinh va'n de phai xac dinh kieu gen bd me de ed loai giao td mong muo'n H i e n tugng thieh nghi cua mgt ca the la sg ddng gdp cua nhdng gen tao ra the he ke tie'p hoac tao ra mgt sd ldn con lai cua nd trong the he ke tiep (Bdu va Lang 2003) Khi gia tri fitness trung binh duge xem xet vdi gdc do nhu vay, ngudi t a se gia dinh r a n g quan the khdng bi b a n che bdi yeu td moi trudng
Neu chdng ta khdng cd nhdng rugng cung cap ngudn ray nau vdi m a t do cao (thi
du nhu J a s m i n e 85, cac gidng nep, v.v ) gia tri thich nghi trung binh se k h d n g
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Trang 7t h a y ddi, t i n h k h a n g ray nau se ed the dn dinh, vdi bg gid'ng dang canh tac tuano-do'i da d a n g ve di truyen cua cay chu N h d n g bien p h a p tac dgng ve mdi
trUdno-n h u "Ba Giam, Ba TatrUdno-ng", "IPM" se r a t td't cho bietrUdno-n p h a p quatrUdno-n ly trUdno-n h u vay
N d n g d a n sd dung h a t gid'ng xac n h a n la khau cd t i n h quyet dinh trong quan ly
t i n h k h a n g r a y nau trong trUdng hgp gen Idiang la gen lan
Kliai t h a c gen mdi Bph-18 t r e n ngudn vat lieu IR65482-7-216-1-2 (dan xua't cua
O australiensis), nhd m a r k e r RM6217, t r e n NST sd 12 (Jena va ctv 2006) Hai gen BphlO va B p h l 8 dugc p h a n tich alen, cho tha'y dd la hai gen gen lien ket theo kieu lap doan ( p h a n ly 15:1) t r e n cdng n h i e m sac the 12 ( J e n a va ctv 2006) Cae gid'ng
t r i e n vgng: OM4498, OM5930, OM2395, OM6055, OM5625, OM5936, OM5628, OM5799, OM7347, OM6840 da dugc khai t h a c hai gen BphlO va B p h l 8 theo hudng
n a y (chgn lgc nhd chi thi p h a n td)
Gen k h a n g B p h l 5 t r e n n h i e m sac t h e so' 4 cung dugc lUu y Ngudn cho la Ida
h o a n g O officinalis, quan t h e duge thu t h a p tai Trung Qud'e Nd dinh vi d quang gida 2 m a r k e r : C820-S11182 (trong dd ed 22 SSR va 25 STS) Nd dinh vi gan t a m ddng, r a t khd lap b a n dd, k h a n a n g tai td hgp t h a p , do ca'u true di n h i i m sac Sd dgng BAC clones cho tha'y t r e n 47 kb chieu dai doan p h a n td muc tieu, ed sg hien dien cua 11 ORFs [phan tich Gensean], vdi k h o a n g each vat ly 1Mb/ 0 di truyen 1
cM (thay vi 260 kb/cM nhU binh thudng) Do dd, chung t a phai thgc h i e n fine map-ping t h a t chi tiet de dd tim m a r k e r tuang dng (Yang va ctv 2004)
Gen k h a n g B p h l 4 t r e n n h i i m sac the so' 3, va B p h l 5 t r e n n h i i m sic the so' 4
dugc d a t t e n mdi trong chuang t r i n h Green Super Rice d Trung Qudc la Q b p h l va Qbph2, do t i n h k h a n g phd r g n g cua chdng (Zhang 2008)
2.3 G e n o m e h o c t r o n g t i n h k h a n g b $ n h d a o o n
TrUde sg k i e n ddng tien hoa cua ky chu va ky sinh [gen R cua cay Ida -i- gen avir cua ky sinh] (Wang va Leung 1999), ngUdi ta dUa r a cac giai p h a p sau:
- Gia t a n g k h a n a n g n g a n can m a n h me sg p h a t sinh ndi (pathogen)
- Sd dung tinh khang sd lugng: lam suy giam sU keo dai giai doan sinh san cua pathogen
- Ddng hoa (cloning) gen k h a n g t h a n h cdng la t i e n de k h i n g dinh ca sd p h a n td
va hoa sinh cua gen k h a n g theo hUdng b e n vdng
- P h a n tieh di truyen cua pathogen: xae dinh gen cua ky sinh la tin hieu cO sd; xac dinh yeu to' p h a t sinh b e n h la cdng eg tim gen k h a n g
2.3.1 Phdn tich di truyen cua Magnaporthe grisea
Dd'i vdi n a m gay benh dao dn, Ralph A Dean va ctv (2005) thugc DH North Carolina State da cdng bd ke't qua ndi tieng ve giai ma bg gen nam, dang t r e n tap chi Nature Sau dd, Ma va ctv (2006), Chen va ctv (2007) nghien cdu toan bg genome eua vi n a m Magnaporthe grisea, gen va benh ly hgc, hien tugng synteny (gen tuang ddng vdi gen cua genome khac) Do ldn cua genome vi n a m nay la 40Mb,
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Trang 8vdi 7 n h i i m sac t h e N a m 1998, ngudi ta t h a n h lap mgt consortium qudc te vdi ten
ggi la "International Rice Blast Genome" (IRBGC) de hgp tac nghien cdu benh djo
dn t r e n cac vdng trdng Ida toan the gidi Sd lugng gen cd trong genome eua vi nam
la 11.109 gen, p h a n bd theo ti le 1/3,5 kb, bao gdm 45% so gen cd m a di truyen ddgc xac dinh P h a n tich Signalp-2.0 (PSORT) cho thay, sd protein chua dugc bie't gan vOi khu vuc chitin la 1.258 Cae DNA ed tinh chat lap lai khong p h a n bd ngSu nhien trong genome ma p h a n bd theo nhdm, khdng cd hien tugng synteny Theo k e t qua hgp tae qud'e te eda consortium nay, ngUdi ta da thiet lap dugc microarray chat lugng cao, ed tinh k h a thi v i m a t thuang mai NhUng phan tich "knockout" va t h e h i e n gen ddi vdi gen muc tieu da cung cap eho chdng ta nhieu kien thdc ve bien dUdng protein, sg dieu chinh nitrogen cua vi n a m trong qua trinh phat sinh b e n h t r e n lua Dac diem eua gen dinh vi telomere se r a t khd tim marker ddng phan ly Gen AvrPit
h e n ket vdi ehi thi p h a n td m355-366 (2,3 cM), gen ArvPia hen ket vdi S487 (3,5 cM) Chung deu dinh vi tai telomere cua n h i i m sac the sd 1 va 7, theo thd tU (Chen va ctv 2007) Do dd, viec tim marker hen ket vdi chung khdng phai la dieu d i dang Trong M grisea hai gen P M K l va C 0 N 7 dai dien cho ldp gen fndi, p h a t s i n h
b e n h khac vdi kieu truyen thdng Ca hai gen P M K l va C0N7 deu cd t i n h c h a t hoai sinh Chdng khdng ky sinh t r e n te bao chu ngay ca trUdng hgp chung da x a m n h a p vao rdi thong qua vet thuang Xu va Hamer (1996) eho rkng P K M l ma hda "MAP kinase", dieu nay cd the kich boat gen tao ra dia bam ed tinh chat chuyen biet, va tao ra sinh tong hgp t h a n h te bao mdi, hinh t h a n h ap lgc tao bUdu Khi vao dugc
te bao cay ehu, P K M l can cd mgt tin hieu eua h a n g loat gen khac, phuc vu cho sinh trudng kieu ky sinh Khae vdi P K M l , gen C0N7 la mgt gen dieu hda (nd l a m nhiem vu dieu tiet cd tinh chat chuyen ma) Nd dieu khien hien tUgng ky s i n h t d kieu hoai sinh (saprophytic) sang kieu ky sinh (parasitic) cua pathogen (Shi 1995) Gen C 0 N 7 cd the dieu khien nhieu gen mgc tieu khac ve m a t chuyen m a di truyen, r a t can cho qda trinh xam n h a p theo ca che "invasion" vao cay chu
Gen C O N l la mgt gen p h a t trien khac cua ca che nay, duge ngUdi t a p h a t h i e n trong dot bien gen gay ra thay ddi ve h i n h thai cua nam, td bao td d a n g h i n h qua
le chuyen t h a n h dang h i n h kim (Shi va Leung 1994) P h a n tich chudi m a di t r u y e n cua CONl cho tha'y khdng cd mgt sU tuang ddng nao ve chudi ky tU n h u t r o n g so' lieu bao quan (database) Ngudi ta khdng biet: ed phai CONl la mgt gen dieu h d a hay chi la mgt chudi ma dan gian gidp cho viec xac dinh cac t h a n h p h a n cau t r u e trong h i n h thai hge te bao
Liu va Dean (1997) chdng minh r a n g sg dot pha eua mdt gen ma hoa "G-protein" thugc the "-subunit" (gen magB) da lam suy giam sg n h i i m benh va k h a n a n g d i n h
cU cua n a m , nhUng cd nhdng bieu hien khiem khuyet da dugc p h a t s i n h t r o n g ca hai giai doan t a n g trUdng va ky sinh cua pathogen Nhdng nghien cdu n h u vay chi
r a r a n g cac gen dieu hda p h a t trien r a t can thie't eho nam, trong qua t r i n h dieu tiet sg ky sinh cua chdng
Ddi vdi n a m M grisea, ed hai loai hinh gen chuyen tinh da dugc clone h d a vdi ky
•:• H Q I N G H I KHOA HOC CONG NGHE T0.\\ QUOC VE BVTV LAN THLT 3 •^
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Trang 9t h u a t "map-based cloning" (Valent va Chumley 1994) Gen chuyen tinh AVR2-YAJVI0 cua gidng Ida dieu khien sg hoat dgng cd t i n h chat khdng tuang hgp (incompatible interaction) trong gidng Ida Yashiro-mochi Protein cua AVR2-YAM0 cd 223 amino acid va the hien md tip "zinc-protease" NgUdi ta gia dinh rang: AVR2-YAM0 ban
t h a n nd edng la "elicitor", edn chdc n a n g "protease" cua nd se cd the san sinh ra the
"elieitor" sau cung Nhdm t h d hai cua gen chuyen t i n h la PWL (viet t a t td chd path-ogenicity on weeping lovegrass) dieu k h i e n t i n h chat ghi n h a n t r e n cay chu Eragrostis curvula (tieng Anh ggi nd la eay weeping lovegrass) (Sweigard va ctv 1995) H a n g loat cac tUang ddng cua gen PWL da dugc clone hda td cac isolate cua
n a m M grisea ky sinh t r e n mgt gidng cd hda b a n (Kang va ctv 1995) Dang hinh ban dau cua gen PWL2 ma hda protein Ua nUdc, giau glycine, the hien mo tip cua chudi ky tg mang tin hieu bi m a t trong sinh vat eukaryote Nhdng thay ddi td ban chat khdng dge sang gay dge cd the tha'y trong trUdng hgp dot bie'n gd'c base cua chudi ma di truyen, hoac trong trUdng hgp thay ddi vung promoter, thay ddi he dieu
k h i e n , lam m a t k h a n a n g the hien gen (Kang va ctv 1995) Leong va ctv (1997) da thgc h i e n ky t h u a t cloning gen avr ed lien quan den tinh chat chuyen biet t r e n gid'ng Ida Co39, p h a n tieh chudi ky tU eho tha'y khdng cd mgt sU tUang ddng nao vdi nhdng gen avr dugc bie't trUde day AvrCo39 ed ba khung dgc ma (ORF), thi nghiem dot bien cho tha'y O R F l va 0 R F 3 r a t can thiet de phgc vg chdc n a n g "avirulence"
2.3.2 Phdn tich di truyen gen khdng benh dao dn cua cdy lua
Nghien cdu di truyen t i n h k h a n g b e n h dao dn cd the ndi duge bat dau td khi Goto t h i e t lap he thd'ng gid'ng chuan ndi dd'i vdi n a m gay benh dao dn t r e n Ida d
N h a t vao dau t h a p nien 1960 (Ou 1985)
Cd k h o a n g 50 gen chu lgc dugc ghi n h a n (Chen va ctv 2005), t a t ca la gen trgi chi trU pi-21 la gen lan (Jeung et al 2007) NgUdi ta da ddng hoa duge 7 gen Pib, Pita, Pi36, Pi9, Pi2, Pid2, Piz-t (Liu et al 2007)
Yoshimichi Fukuta (2008) thugc chuong t r i n h hgp tac JIRCAS va IRRI ve benh dao dn t r e n Ida da nghien edu cac dieu kien de cd t i n h k h a n g k h a n g b e n h dao dn Ida trd n e n ben vdng Cd t r e n 80 gen va QTL dieu k h i e n t i n h k h a n g benh dao dn
da dugc bao eao, nhUng nhieu gen dugc tim t h a y t r e n cung loci Khdng ai cd the dinh t i n h va p h a n biet tdng gen k h a n g rieng le Hien t r a n g nghien cdu ve di
truyen t i n h k h a n g vin edn phUc t a p Mgt trong n h d n g ly do dd la thieu he thdng
gid'ng chuan k h a n g t r e n n h d n g ndi chuan (blast isolates) Can phai l a m rd tinh chat gay b e n h cua cac isolates va t i n h k h a n g cua cay chu Giai phap: bg gidng chuan k h a n g qud'e te mdi dang dugc p h a t t r i e n bdi IRRI va N h a t Nhdng gidng chuan k h a n g nay m a n g mgt gen dan va phu t r e n 24 kieu gen khac Dieu dd se tao
t h u a n lgi cho viec dieu t r a n g a n h a n g gen, p h a t t r i e n he t h d n g chuan khang, va
l a m rd sg k h a c biet eua ndi (isolates) H a n che: mgt qudc gia hay mgt td chdc khdng the h o a n chinh ndi dung neu t r e n ma can td chdc m a n g t i n h quo'c te sau rgng, cd
m a n g ludi hgp tac nghien cdu, chia se t h d n g tin, vat lieu n g a n h a n g gen, ngudn pathogen Mgt dg an nghien cdu da dugc t h a n h lap ed t e n la "Blast Research Network for Stable Rice Production" (Fukuta 2008)
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Trang 10Trong mgt tuang tac giufa ky sinh va ky chu cd t i n h c h a t ddng tie'n h d a cao, tinh
k h a n g b e n h cd t h e dugc chia ra t h a n h hai dang: (1) t i n h k h a n g ve cha't lugng (qual-itative)- de cap de'n k h a n a n g n g a n can m a n h me sU p h a t sinh cac ndi chuj^en t i n h (strain) cua "pathogen", n g a n can sU sinh s a n cua pathogen, t r o n g khi t i n h k h a n g
sd lugng (quantitative) l a m suy giam sg keo dai giai doan sinh s a n cua "pathogen", theo k h a i niem tucmg tac ca ban; (2) t i n h k h a n g chuyen t i n h ddi vdi ndi (race) dugc dung de d i i n ta mgt p h a n Ung k h a n g b e n h ddi vdi mgt kieu gen cua mdt pathogen chuyen biet nao dd, va t i n h k h a n g khdng chuyen t i n h la p h a n dng k h a n g trong ta't
ca kieu gen k h a c nhau (Wang va Leung 1999)
Gen dinh vi t r e n cac n h i i m sac the cung ddgc bao cao vdi it nha't 18 loci lien quan den t i n h k h a n g sd lugng (Kinoshita 1995, Yu va ctv 1991, Mackill va Bonman
1992, Zhu va ctv 1993, Wang va ctv 1994, Naqvi va Chattoo 1996)
Tuy nhien, cho de'n nay viec cloning t h a n h cdng gen k h a n g dao dn van chUa dugc ghi nhan, mgt sd gen Pi-b, Pi-ta, Pi-ta2, Pi-5, Pi-7 dang duge hoan thien mgt each tieh cge tai nhieu phdng thi nghiem tren the gidi (Tsunoda va ctv 1998, Wang va ctv 1998b, Chen va ctv 1998), gen Pi36 tren n h i i m sac the sd 8 (Liu va ctv 2007), gen Pi40(t) thugc mdtip NBS-LRR tren n h i i m sac the sd 6 (Jeung va ctv 2007), sU tien hoa Pi-ta locus cua Oryza rufipogon (Huang va ctv 2008) cung dugc cdng bd gan day Vien Lda Ddng b a n g sdng Cdu Long thgc h i e n khai t h a c Ida hoang, Te Tep, Sdc Nau lam ngudn eung cap gen k h a n g va ddng hoa gen Pi2, d i n h vi gida 2 R F L P
m a r k e r la RG64 (phan cat bang Xbal) va L P O l l l - 1 1 2 ( p h a n cat b a n g B g U l ) t r e n nhiem sac the so' 6 va tim kiem gen mdi k h a n g ddng n a m cd ddc t i n h m a n h nha't trong bg sUu tap la O M P l (Bdu 2002, Bdu va Lang 2003, 2007, 2008, L a n g va Bdu
2002, 2003, Brar va ctv 2005)
Gen Pi-ta2 va Pi-ta lien k e t r a t chat, hoac cd the xem dd la hai alen k h a c nhau dinh vi t r e n cung mgt locus, hai gen nay da dugc t h i e t lap b a n dd di truyen, dinh
vi d t a m dgng cua n h i e m the so' 12 (Wu va ctv 1996, N a k a m u r a va ctv 1997) Ben canh dd, Wu va ctv (1996) da thie't lap b a n dd di truyen va b a n dd v a t ly b a n g each sd dgng BAC clone, quet r a t ky khu vgc gen Pi-ta, vdi 3 m a r k e r p h a n td lien ke't c h a t ' t r o n g k h o a n g 0,5 cM Tuang tg n h u vay, N a k a m u r a va ctv (1997) da t h i e t lap mgt "contig map", vdi qui md quet 300 kb, va m a r k e r lien k e t vdi gen Pi-ta2 trong khoang 0,3 cM Tuy nhien, vdng t a m dgng la noi t h e h i e n r a t tha'p k h a n a n g tai td hgp va the hien t a n sua't cao cua chudi ma lap lai Dieu n a y dat r a cho chdng
ta n h d n g khd k h a n trong viec tie'p can vdi gen muc tieu bkng ky t h u a t "chromosome walking" C a n day, Rybka va ctv.(1997) da xac dinh gen Pi-ta2 lien ke't vdi hai
m a r k e r ke can vdi k h o a n g each di truyen khoang 0,3 cM Gen Pi-ta dugc d i n h vi
t r e n ban dd d vi tri chdng lap vdi Pi-ta2 bkng phuang p h a p p h a n tich kieu gen theo gian dd (graphical genotype) cua mgt ddng dkng gen Ke't qda ggi ra cho chdng ta
k h a i niem: hai gen n a y ed quan he vdi nhau ve ehdc n a n g , tuang tac allelic, hoac
it nha't chdng lien k e t vdi nhau r a t chat, va chdng cd t h e ed cdng mgt ngudn gen
td tien (Rybka va ctv 1997)
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