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Published online: 22 October 2008 | doi:10.1038/nchina.2008.245

Rice genetics: Good harvest

Felix Cheung

Introduction

© (2008) Nature Genetics

Certain rice traits are controlled not by a single gene, but by the interaction of a group of genes. For example, traits that affect rice yields, such as the number and weight of grains, are regulated in this manner. Zuhua He at the Chinese Academy of Sciences in Shanghai and co-workers¹ have identified GIF1 to be one of the many genes responsible for controlling crop grain-filling — an important factor that determines the final grain weight and thereby grain yield.

A common strategy for the large-scale discovery of gene functions is to generate a population of mutants through random DNA insertions and then screen for traits of interest. The researchers therefore looked for rice with grain-filling defects in a mutant population of Japonica cultivar grown in China.

One mutant, of which the expression of gif1 had been restricted, showed slower grain-filling. On the outside, the mutant (pictured bottom) might look the same as normal rice (pictured top). But on the inside, its grains were actually smaller, chalkier, weighed less and contained lower levels of starch. He and co-workers later found out that GIF1 encodes an enzyme that catalyses the breakdown of sugars into starch.

Also, the grain-filling of cultivated rice carrying GIF1 was less complete than that of wild rice carrying GIF1. The researchers hold the opinion that the difference between cultivated and wild-rice GIF1 is probably a result of accumulated mutations in the gene's regulatory sequence through domestication.

The authors of this work are from:
Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China; China National Rice Research Institute, Hangzhou, China; Zhejiang Academy of Agricultural Sciences, Hangzhou, China; School of Life Sciences, Fudan University, Shanghai, China; Department of Biology and the Huck Institutes of Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA; College of Agriculture, South China Agricultural University, Guangzhou, China.

Reference

1. Wang, E. et al. Control of rice grain-filling and yield by a gene with a potential signature of domestication. Nature Genet. doi: 10.1038/ng.220 (2008). | Article |