利用CRISPR/Cas9技术创制广亲和水稻温敏雄性不育系

Creation of Thermo-sensitive Genic Male Sterile Rice Lines with Wide Compatibility Based on CRISPR/Cas9 Technology

【目的】为突破传统杂交转育方法对水稻两系不育系选育的限制,利用CRISPR/Cas9技术对籼型恢复系台恢31的温敏雄性核不育基因TMS5进行编辑,以获得全新水稻温敏雄性不育系。【方法】选择水稻温敏不育基因TMS5第1外显子的2段序列作为靶点,构建双靶点pHUE411-TMS5-gRNA载体,通过农杆菌侵染获得116株T0代转基因植株。【结果】经鉴定获得3种类型纯合突变体tms5-1、tms5-2和tms5-3,每一种突变均导致TMS5氨基酸序列的缺失。分期播种试验结果显示,幼穗分化敏感期温度为27℃时,tms5-1和tms5-3自交结实率分别为0.56%、0.03%,表现为高度不育,而tms5-2则完全不育。与野生型台恢31相比,不育系TB52S(即tms5-2)单株穗数增多,穗长变短,株高及每穗总粒数相较WT均下降25%,花药发白瘦小,无花粉粒充实,柱头、颖壳没有显著差异。TB52S幼穗分化4期时进行温度处理,确认TB52S的育性转换温度为26℃。TB52S分别与籼、粳型恢复系配组,F1的结实率超过90%。【结论】利用CRISPR/Cas9技术对籼型恢复系台恢31的温敏雄性核不育基因TMS5进行编辑,获得能够稳定遗传的水稻广亲和温敏雄性不育系TB52S,为两系不育系选育提供新的技术支撑。

【Objective】In order to break the fetters in traditional hybridization in the breeding of genic male sterile rice lines,the thermo-sensitive genic male sterility gene TMS5 was edited by CRISPR/Cas9 technology to create new genic male sterile lines using indica restorer line Taihui 31 as material.【Method】Two sequences in the first exon of TMS5 were chosen as target sites for the construction of vector pHUE411-TMS5-gRNA and 116 T0 generation transgenic plants were obtained by Agrobacterium infection method.【Result】Three homozygous mutants,tms5-1,tms5-2 and tms5-3 with amino acid deletion in TMS5 were verified by PCR and sequencing.The split sowing experiment showed that the self-fertilization rate of tms5-1 and tms5-3 were 0.56%and 0.03%at 27℃,respectively.Meanwhile,at the same temperature,the pollen of tms5-2 turned to be completely sterile.Compared with Taihui 31(WT),TB52S(tms5-2)had more panicles,shorter panicle length.Its plant height and grain numbers per panicle reduced to nearly three quarters of WT.Furthermore,except for smaller anther with no pollens,the stigma,palea and lemma of TB52S didn’t change significantly as compared with WT.The fertility transfer temperature of TB52S was confirmed as 26℃according to the temperature test during the IV phase of young panicle differentiation.Last but not least,the seed setting rate of hybrid F1 derived from the cross between TB52S and indica or japonica restorer lines was beyond 90%.【Conclusion】Using CRISPR/Cas9 technology,we obtained thermo-sensitive genic male sterile line TB52S which was genetically stable.It provides new technical support for the breeding of genic male sterile lines.