华南农大陈乐天团队利用基因工程手段克服水稻籼粳不育

水稻籼粳交所产生的后代农艺性状优良却表现不育,这极大地限制了水稻杂种优势的利用。最近,华南农业大学陈乐天团队利用RNAi和CRISPR/Cas9技术敲除SaFSaM基因获得了水稻广亲和品种。

籼粳稻杂种不育基因位点Sa是由两个相邻基因SaFSaM组成的复合位点,其中SaF+和SaM+、SaM-共同参与调控水稻杂种不育(“+”表示籼稻位点,“-”表示粳稻位点)。SaFSaM分别编码F-box蛋白和SUMOE3连接酶。研究人员利用RNAi干涉和CRISPR/Cas9技术敲除SaFSaM基因后,水稻籼粳不育现象明显减弱。研究还发现,一些水稻材料天然地存在着广亲和位点Sa-n,可保证籼粳杂交的育性。

该研究为利用基因工程手段克服水稻杂种不育提供了很好地范例。

J Integr Plant Biol. 23 August 2017.

Suppression or knockout of SaF/SaM overcomes the Sa-mediated hybrid male sterility in rice.

Author

Xie Y, Niu B, Long Y……Ren D, Liu YG, Chen L*.

State Key Laboratory forConservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, China.

Abstract

Hybrids between the indica and japonica subspecies of rice (Oryza sativa) are usually sterile, which hinders utilizationof heterosis in the inter-subspecific hybrid breeding. The complexlocus Sa comprises two adjacentlylocated genes, SaF and SaM, which interact to cause abortion of pollen grains carrying the japonica allele in japonicaindica hybrids. Here we showed that silencing of SaF or SaM by RNA interference restored male fertility in indicajaponica hybrids with heterozygous Sa. We further used clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9-based genome editing to knockout the SaF and SaM alleles, respectively, of an indica rice line to create hybrid-compatible lines. The resultant artificial neutral alleles did not affect pollen viability and other agricultural traits, but did breakdown the reproductive barrier in the hybrids. We found that some rice lines have natural neutral allele Sa-n, which was compatible with the typical japonica or indica Sa alleles in hybrids. Our results demonstrate that SaF and SaM are required for hybrid male sterility, but are not essential for pollen development. This study provides effective approaches forthe generation of hybrid-compatible lines by knocking out the Sa locus or using the natural Sa-n allele to overcome hybrid male sterility in rice breeding.