Cloning of Long Sterile Lemma (lsl2), A Single Recessive Gene Regulating Spike Germination in Rice (Oryza Sativa L.)

Abstract

Background: Rice is a typical monocotyledonous plant and an important cereal crop. The structural units of rice flowers are spikelets and florets. Floral organ development and spike germination affect rice reproduction and yield. Results: In this study, we identified a novel long sterile lemma (lsl2) mutant from an EMS population. First, we mapped the lsl2 gene between the markers Indel7-22 and Indel7-27, which encompasses a region of 25 kb. The rice genome annotation indicates the presence of four candidate genes in this region. Through gene prediction and cDNA sequencing, we confirmed that the target gene in the lsl2 mutant is allelic to LONG STERILE LEMMA1 (G1)/ELONGATED EMPTY GLUME (ELE), hereafter referred to as lsl2. Further analysis showed a one-amino acid change, serine (Ser) 79 mutated to proline (Pro), in the lsl2 protein had compared with LSL2, which may change the function of the LSL2 protein. The knockout experiments showed that the lsl2 gene is responsible for the long sterile lemma phenotype. The lsl2 gene may reduce the damage caused by spike germination by decreasing the seed germination rate, and yet other agronomic traits of rice are not affected in the lsl2 mutant. Taken together, our results demonstrate that the lsl2 gene will have specific application prospects in future rice breeding.Conclusions: The lsl2 gene is responsible for the long sterile lemma phenotype, and may reduce the damage caused by spike germination by decreasing the seed germination rate.