A new gene for rice grain dropping regulation was found

The seeds of wild rice fall off automatically when they are mature, which is conducive to the spread and survival of seeds However, the "easy falling grain" has negative effects on the yield reduction of cultivated rice varieties aiming at harvesting mature rice Our ancestors began to domesticate rice from the point of view of reducing the ability of selective threshing very early As a matter of fact, there is a great difference in seed dropping ability of modern cultivated rice, which shows that seed dropping is a complex character controlled by multiple genes It is of great agricultural significance to have a thorough and comprehensive understanding of the mechanism of rice grain dropping regulation and reduce the yield loss caused by grain dropping Zhou Yan, Lu Danfeng and other researchers from Hanbin research group, Institute of plant ecology, Shanghai Institute of life sciences, Chinese Academy of Sciences / National Center for gene research, introduced the fourth chromosome of wild rice w1943 into the background of cultivated rice guangluai4, and constructed a material SL4 containing known seed dropping genes SH4 and qsh1 and showing extremely easy seed falling Through γ - ray mutagenesis of SL4, they screened two mutants, shat1 and shat2, which did not drop grains at all These two mutants can not form abscission layer, so it needs a lot of pulling force to separate the seeds from the branchlets after the seeds mature Through map based cloning and genetic transformation, the researchers determined that the shat1 gene is an ap2 transcription factor, which has high homology with the apetala2 gene of Arabidopsis and is highly expressed in the isolated layer Shat2 was identified as a new allele of SH4 gene Different from the previously reported single amino acid substitution mutation type of SH4 in cultivated rice, shat2 is a frameshift mutation, so it is named sh4-2 The researchers further elaborated the genetic relationship among the three genes of shat1, SH4 and qsh1 by means of in situ hybridization analysis: SH4 promotes the expression of shat1 in the abscission layer, and in turn, shat1 also maintains the expression of SH4 in the abscission layer The consistent expression of the two genes in the abscission layer is necessary for the correct formation of the abscission layer Qsh1 acts on the downstream of SH4 and shat1, and promotes the formation of abscission by maintaining the continuous expression of shat1 and SH4 in the abscission layer In this study, we used a clever way to search for the suppressors to find the new genes, and at the same time associated with the known genes, which opened a new field for the research of rice dropping On March 9, the research paper "genetic control of seed shattering in Rice by the AP2 transcription factor shattering abortion1" was published online in the international academic journal the plant cell At the same time, the editorial review article shat1 was also published, A new player in seed shattering of rice spoke highly of this work.