來自中國和美國的科學(xué)家在新一期《自然—遺傳學(xué)》雜志電子版上報(bào)告說,，他們發(fā)現(xiàn)水稻的一個(gè)特定基因負(fù)責(zé)控制米粒的大小和分量,。
參與研究的賓夕法尼亞大學(xué)華人科學(xué)家馬宏說，他們的研究工作表明,，通過加強(qiáng)某個(gè)特定基因的表達(dá),，可以實(shí)現(xiàn)稻米增產(chǎn)的目標(biāo)。這個(gè)新基因的發(fā)現(xiàn)將有助于培育高產(chǎn)轉(zhuǎn)基因水稻新品種,。
領(lǐng)導(dǎo)此項(xiàng)研究的中國科學(xué)院生物學(xué)家何祖華在新聞公報(bào)中介紹說,，他們首先在水稻中篩選出一些米粒分量明顯不足的變異植株，并從中鑒別出一種特殊的變異植株,，這一植株根本無法長出正常大小的米粒,。于是，他們對(duì)該植株進(jìn)行進(jìn)一步的研究,，發(fā)現(xiàn)它的GIF1基因出現(xiàn)變異,。
GIF1基因負(fù)責(zé)控制水稻中轉(zhuǎn)化酶的活動(dòng)。轉(zhuǎn)化酶位于水稻的細(xì)胞壁上,，負(fù)責(zé)將蔗糖轉(zhuǎn)化為用于合成淀粉的物質(zhì),，這些物質(zhì)繼續(xù)發(fā)育后長成米粒。如果轉(zhuǎn)化酶不活躍,，水稻就很難長出飽滿的顆粒,。
試驗(yàn)發(fā)現(xiàn)，如果GIF1基因正常無變異,，轉(zhuǎn)化酶活性正常,；如果GIF1因發(fā)生變異而表達(dá)不夠，轉(zhuǎn)化酶的活性僅為正常水稻的17%,。研究小組培育出一種轉(zhuǎn)基因水稻,，使GIF1基因過度表達(dá)，結(jié)果發(fā)現(xiàn),，這種水稻的顆粒比正常水稻的大,，分量也要重。
科學(xué)家希望他們的這一成果能夠幫助水稻育種科研人員培育出顆粒更大,、更飽滿的新雜交品種,。(生物谷Bioon.com)
生物谷推薦原始出處:
Nature Genetics Published online: 28 September 2008 | doi:10.1038/ng.220
Control of rice grain-filling and yield by a gene with a potential signature of domestication
Ertao Wang1,2, Jianjun Wang3, Xudong Zhu2, Wei Hao1, Linyou Wang3, Qun Li1, Lixia Zhang3, Wei He1, Baorong Lu4, Hongxuan Lin1, Hong Ma5, Guiquan Zhang6 & Zuhua He1
1 Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China.
2 China National Rice Research Institute, 359 TiyuChang Road, Hangzhou 31006, China.
3 Zhejiang Academy of Agricultural Sciences, 198 Shiqiao Road, Hangzhou 310021, China.
School of Life Sciences, Fudan University, 220 Handan Road, Shanghai 200433, China.
4 Department of Biology and the Huck Institutes of Life Sciences, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
5 College of Agriculture, South China Agricultural University, Guangzhou 510642, China.
Grain-filling, an important trait that contributes greatly to grain weight, is regulated by quantitative trait loci and is associated with crop domestication syndrome1, 2, 3, 4. However, the genes and underlying molecular mechanisms controlling crop grain-filling remain elusive. Here we report the isolation and functional analysis of the rice GIF1 (GRAIN INCOMPLETE FILLING 1) gene that encodes a cell-wall invertase required for carbon partitioning during early grain-filling. The cultivated GIF1 gene shows a restricted expression pattern during grain-filling compared to the wild rice allele, probably a result of accumulated mutations in the gene's regulatory sequence through domestication. Fine mapping with introgression lines revealed that the wild rice GIF1 is responsible for grain weight reduction. Ectopic expression of the cultivated GIF1 gene with the 35S or rice Waxy promoter resulted in smaller grains, whereas overexpression of GIF1 driven by its native promoter increased grain production. These findings, together with the domestication signature that we identified by comparing nucleotide diversity of the GIF1 loci between cultivated and wild rice, strongly suggest that GIF1 is a potential domestication gene and that such a domestication-selected gene can be used for further crop improvement.
