Background: Rice is a typical monocotyledonous plant and an important cereal crop. The structural units of rice flowers are spikelets and florets, and 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 25-kb region. The rice genome annotation indicated 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 of the lsl2 and LSL2 proteins showed a one-amino-acid change, namely, the mutation of serine (Ser) 79 to proline (Pro) in lsl2 compared with LSL2, and this mutation might change the function of the protein. Knockout experiments showed that the lsl2 gene is responsible for the long sterile lemma phenotype. The lsl2 gene might reduce the damage induced by spike germination by decreasing the seed germination rate, but other agronomic traits of rice were not changed 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 might reduce the damage induced by spike germination by decreasing the seed germination rate.

Background: Rice is a typical monocotyledonous plant and an important cereal crop. The structural units of rice flowers are spikelets and florets, and 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 25-kb region. The rice genome annotation indicated 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 of the lsl2 and LSL2 proteins showed a one-amino-acid change, namely, the mutation of serine (Ser) 79 to proline (Pro) in lsl2 compared with LSL2, and this mutation might change the function of the protein. Knockout experiments showed that the lsl2 gene is responsible for the long sterile lemma phenotype. The lsl2 gene might reduce the damage induced by spike germination by decreasing the seed germination rate, but other agronomic traits of rice were not changed 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 might reduce the damage induced by spike germination by decreasing the seed germination rate.

Rice blast is a detrimental rice disease caused by the fungus Magnaporthe oryzae. Here, we identified a resistance gene from the rice cultivar Fuhui 2663 which is resistant to the rice blast isolate KJ201. Through isolated population analyses and sequencing approaches, the candidate gene was traced to chromosome 12. With the use of a map-based cloning strategy, the resistance gene was ultimately mapped to an 80-kb resistance locus region containing the Pita gene. Candidate gene prediction and cDNA sequencing indicated that the target resistance gene in Fuhui 2663 was allelic to Pita, thus being referred to as Pita-R hereafter. Further analysis showed that the Pita-R protein had one amino acid change: Ala (A) residue 918 in Pita-R was replaced by Ser (S) in Pita-S, leading to a significant change in the 3D structure of the Pita-S protein. CRISPR/Cas9 knockout experiments confirmed that Pita-R is responsible for the resistance phenotype of Fuhui 2663. Importantly, Pita-R did not affect the main agronomic traits of the variety compared to the Pita gene as verified by knockout experiments, indicative of potential applications of Pita-R in broader breeding programs. Furthermore, a Pita-R-dCAPS molecular marker with good specificity and high efficiency was developed to facilitate rice breeding for resistance to this devastating disease.