日本发现能使米粒变大的基因 有望促进水稻增产

日本名古屋大学一个研究小组在新一期美国《国家科学院学报》网络版上报告说，他们发现了一种能使米粒变大的基因。这一发现将有望促进水稻增产。

研究小组对米粒很短的日本米品种“日本晴”和米粒细长的印度米品种“Kasalath”的基因进行比较，发现GW6a基因能控制米粒大小，而且“Kasalath”体内这种基因的功能要比“日本晴”强大很多。

于是，研究小组将“Kasalath”的GW6a基因植入“日本晴”体内，结果“日本晴”米粒变大，体积和重量比以前增加了约15％。

此外，研究小组还发现，植入GW6a基因后，“日本晴”植株自身也增大。提高这种基因的功能，米粒还能变得更大，而遏制其功能，米粒则会变小。

除基因重组外，研究小组通过杂交进行品种改良，将这种基因植入其他水稻品种后，也得到了同样的结果。

研究小组指出，同样的技术还有可能应用到小麦和玉米上。研究人员认为，这项研究成果将有助大幅提高谷物的产量，有望为减轻世界粮食危机做出贡献。

Rare allele of a previously unidentified histone H4 acetyltransferase enhances grain weight, yield, and plant biomass in rice

Abstract Grain weight is an important crop yield component; however, its underlying regulatory mechanisms are largely unknown. Here, we identify a grain-weight quantitative trait locus (QTL) encoding a new-type GNAT-like protein that harbors intrinsic histone acetyltransferase activity (OsglHAT1). Our genetic and molecular evidences pinpointed the QTL-OsglHAT1’s allelic variations to a 1.2-kb region upstream of the gene body, which is consistent with its function as a positive regulator of the traits. Elevated OsglHAT1 expression enhances grain weight and yield by enlarging spikelet hulls via increasing cell number and accelerating grain filling, and increases global acetylation levels of histone H4. OsglHAT1 localizes to the nucleus, where it likely functions through the regulation of transcription. Despite its positive agronomical effects on grain weight, yield, and plant biomass, the rare allele elevating OsglHAT1 expression has so far escaped human selection. Our findings reveal the first example, to our knowledge, of a QTL for a yield component trait being due to a chromatin modifier that has the potential to improve crop high-yield breeding.

原文链接：http://www.pnas.org/content/early/2014/12/18/1421127112.full.pdf+html?with-ds=yes