近日,，國際著名雜志Cell Research在線報道了華南農(nóng)業(yè)大學(xué)莊楚雄研究員課題組的最新研究成果“Photoperiod- and thermo-sensitive genic male sterility in rice are caused by a point mutation in a novel noncoding RNA that produces a small RNA，”,，文章中,，研究者成功克隆了水稻光溫敏核不育基因。該論文共同第一作者是博士生周海及劉勤堅,。
利用光溫敏不育系培育的兩系雜交水稻免除了保持系,，在不同的光溫條件下既可以作為不育系與恢復(fù)系雜交制種，又可以自身繁殖,，從而簡化了繁種制種程序,，降低了雜交種子生產(chǎn)成本。更重要的是,，兩系雜交稻的配組較自由,，選配到優(yōu)良組合的機(jī)率較高。因此,，兩系雜交育種是我國在水稻雜種優(yōu)勢利用的重大突破,。目前，兩系雜交稻育種主要利用溫敏不育系,。
“培矮64S”是由國家雜交水稻工程技術(shù)研究中心的羅孝和研究員以我國水稻育種家石明松發(fā)現(xiàn)的粳稻光敏不育系“農(nóng)墾58S”為供體,，以“培矮64”為受體，以回交選育成的秈型溫敏核不育系,。由于其廣親和性及良好的農(nóng)藝性狀,，“培矮64S”已成為了推廣面積最大的兩系雜交稻不育系親本,。“培矮64”和多個秈型不育系雖然由“農(nóng)墾58S”轉(zhuǎn)育而來，但它們主要表現(xiàn)出溫敏不育特性而非光敏不育特性,。這種溫敏不育性的遺傳位點是否來源于“農(nóng)墾58S”,，粳型“農(nóng)墾58S”的光敏不育性和它的秈型衍生系的溫敏不育性是否由相同的基因控制，以及它們的分子調(diào)控機(jī)制有何異同等重要問題一直不清楚。
在國家重大基礎(chǔ)研究計劃（973）的支持下,，該課題組經(jīng)多年的研究發(fā)現(xiàn),，“培矮64S”溫敏不育性主要受第12染色體的一個主效基因座p/tms12-1控制。p/tms12-1是一個非編碼RNA基因,，它的原始轉(zhuǎn)錄本經(jīng)過至少2次加工產(chǎn)生一個小RNA,。與正常水稻品種相比，溫敏不育水稻在該小RNA序列內(nèi)存在一個單堿基突變,。研究結(jié)果進(jìn)一步表明，“農(nóng)墾58S”也具有相同的該突變基因,，這個單堿基突變是在秈稻產(chǎn)生溫敏不育性和在粳稻產(chǎn)生光敏不育性的共同原因,。在正常水稻中,，野生型P/TMS12-1的表達(dá)抑制了溫敏或光敏不育的發(fā)生,。而溫敏和光敏不育水稻中，p/tms12-1的該突變影響了小RNA的表達(dá)水平及其可能與靶基因的互作能力而產(chǎn)生雄性不育,。該成果在水稻中率先發(fā)現(xiàn)了一類新的小RNA作為水稻光溫敏育性轉(zhuǎn)換的重要調(diào)控因子,。
該項研究成果與近日報道的華中農(nóng)業(yè)大學(xué)張啟發(fā)研究團(tuán)隊對“農(nóng)墾58S”該相同光敏不育基因克隆的成果代表了我國在雜交稻分子基礎(chǔ)研究領(lǐng)域的重大突破，為進(jìn)一步闡明光溫條件控制水稻育性轉(zhuǎn)換的分子機(jī)制,，指導(dǎo)兩系雜交稻育種,，深入利用水稻雜種優(yōu)勢具有深遠(yuǎn)的意義。（生物谷Bioon.com）
doi:10.1038/cr.2012.28
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Photoperiod- and thermo-sensitive genic male sterility in rice are caused by a point mutation in a novel noncoding RNA that produces a small RNA
Hai Zhou, Qinjian Liu, Jing Li, Dagang Jiang, Lingyan Zhou, Ping Wu, Sen Lu, Feng Li, Liya Zhu, Zhenlan Liu, Letian Chen, Yao-Guang Liu, Chuxiong Zhuang
Photoperiod- and thermo-sensitive genic male sterility (PGMS and TGMS) are the core components for hybrid breeding in crops. Hybrid rice based on the two-line system using PGMS and TGMS lines has been successfully developed and applied widely in agriculture. However, the molecular mechanism underlying the control of PGMS and TGMS remains obscure. In this study, we mapped and cloned a major locus, p/tms12-1 (photo- or thermo-sensitive genic male sterility locus on chromosome 12), which confers PGMS in the japonica rice line Nongken 58S (NK58S) and TGMS in the indica rice line Peiai 64S (PA64S, derived from NK58S). A 2.4-kb DNA fragment containing the wild-type allele P/TMS12-1 was able to restore the pollen fertility of NK58S and PA64S plants in genetic complementation. P/TMS12-1 encodes a unique noncoding RNA, which produces a 21-nucleotide small RNA that we named osa-smR5864w. A substitution of C-to-G in p/tms12-1, the only polymorphism relative to P/TMS12-1, is present in the mutant small RNA, namely osa-smR5864m. Furthermore, overexpression of a 375-bp sequence of P/TMS12-1 in transgenic NK58S and PA64S plants also produced osa-smR5864w and restored pollen fertility. The small RNA was expressed preferentially in young panicles, but its expression was not markedly affected by different day lengths or temperatures. Our results reveal that the point mutation in p/tms12-1, which probably leads to a loss-of-function for osa-smR5864m, constitutes a common cause for PGMS and TGMS in the japonica and indica lines, respectively. Our findings thus suggest that this noncoding small RNA gene is an important regulator of male development controlled by cross-talk between the genetic networks and environmental conditions.
