Hybrid rice has greatly contributed to the global increase of rice productivity. A major component that facilitated the development of hybrids was a mutant showing photoperiod-sensitive male sterility (PSMS) with its fertility regulated by day length. Transcriptome studies have shown that large portions of the eukaryotic genomic sequences are transcribed to long noncoding RNAs (lncRNAs). However, the potential roles for only a few lncRNAs have been brought to light at present. Thus, great efforts have to be invested to understand the biological functions of lncRNAs. Here we show that a lncRNA of 1,236 bases in length, referred to as long-day–specific male-fertility–associated RNA (LDMAR), regulates PSMS in rice. We found that sufficient amount of the LDMAR transcript is required for normal pollen development of plants grown under long-day conditions. A spontaneous mutation causing a single nucleotide polymorphism (SNP) between the wild-type and mutant altered the secondary structure of LDMAR. This change brought about increased methylation in the putative promoter region of LDMAR, which reduced the transcription of LDMAR specifically under long-day conditions, resulting in premature programmed cell death (PCD) in developing anthers, thus causing PSMS. Thus, a lncRNA could directly exert a major effect on a trait like a structure gene, and a SNP could alter the function of a lncRNA similar to amino acid substitution in structural genes. Molecular elucidating of PSMS has important implications for understanding molecular mechanisms of photoperiod regulation of many biological processes and also for developing male sterile germplasms for hybrid crop breeding.
雜交水稻極大地推動(dòng)水稻糧食產(chǎn)量的提高。其中一個(gè)可受日照長(zhǎng)度調(diào)控的光敏雄性不育PSMS突變體的應(yīng)用對(duì)雜交水稻的發(fā)展起到關(guān)鍵的作用。轉(zhuǎn)錄組分析發(fā)現(xiàn)真核基因組的序列的很大部分是轉(zhuǎn)錄成長(zhǎng)鏈的非編碼RNAs（IncRNAs）。然而，當(dāng)前我們僅發(fā)現(xiàn)了一些IncRNA的潛在作用，還需要努力去了解探索更多的IncRNAs生物學(xué)功能。本文中，我們發(fā)現(xiàn)了一個(gè)長(zhǎng)度為1236bp，且與長(zhǎng)光照下特異的雄性不育相關(guān)的RNA分子（LDMAR），其調(diào)控這水稻光敏雄性不育PSMS表型。長(zhǎng)日照條件下，足夠的LDMAR轉(zhuǎn)錄量是維持正?；ǚ郯l(fā)育所必需的。但由于一個(gè)自發(fā)的單堿基突變?cè)斐蒐DMAR的二級(jí)結(jié)構(gòu)的改變，導(dǎo)致了LDMAR在特異的長(zhǎng)日照下轉(zhuǎn)錄量降低，結(jié)果造成正處于發(fā)育的花藥進(jìn)入程序化死亡（PCD）提前即產(chǎn)生PSMS。該IncRNA類似一個(gè)結(jié)構(gòu)基因直接控制該表現(xiàn)，該SNP如同結(jié)構(gòu)基因氨基酸的替換一樣也能導(dǎo)致了IncRNA功能的變化。該P(yáng)SMS的基因發(fā)現(xiàn)讓我們對(duì)許多光敏調(diào)控的分子機(jī)制有了更深入的了解，也有利于雄性不育的種資資源在雜交水稻育種的利用。