Cloning of long sterile lemma (lsl2), a single recessive gene that regulates 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, 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.

Genetic control of branching patterns in grass inflorescences

“…Although many lines of evidence support the inference that these are sterile lemmas, they are expanded bracts without an axillary meristem so share some characteristics with glumes. Mutations in G1 / LONG SLENDER LEMMA1 ( Yoshida et al, 2009 ; Yang et al, 2020 ) shift the size and cellular morphology of the sterile lemmas to look more like true lemmas, whereas mutations in other genes lead to stronger similarity between the sterile lemmas and rudimentary (true) glumes (summarized by Ren et al, 2018 ; Xu et al, 2020) . However, none of the mutants leads to production of an axillary FM, as would be expected if the sterile lemmas were fully converted to true lemmas.…”

Evidence and Impacts of Nanoplastic Accumulation on Crop Grains

“…In adult rice plants, PS‐NPs were also detected in spikes by SEM and laser confocal microscope (Figure S7, Supporting Information), whose germination is an important factor affecting the yield and processing quality of rice grain. [ 33 ] Ten days after flowering, the husk of immature rice grains in the grouting period was removed, and the liquid starch was subjected to fluorescence imaging. Nanoplastics entered the grain at the early grain‐setting stage of rice (Figure S8, Supporting Information).…”

A homologous gene of OsREL2/ASP1, ASP-LSL regulates pleiotropic phenotype including long sterile lemma in rice

“…Phylogenetic analysis revealed that mutation was occurred in highly conserved site and have been reported in maize, sorghum and rice [1,49]. This site can be targeted by molecular breeder to solve the specific problem of germination in hybrid rice [51]. Protein of this site may have specific binding activity to some other genes that regulate different traits including the development of lemma [48].…”

“…Most of them are homologous to Arabidopsis and have a certain degree of conservation. These findings provide a basis for studying more about the regulation mechanism of rice flower development, without disturbing other major agronomic yield traits [51,52]. In grasses, these homologous proteins can interact with ETHYLENE RESPONSE FACTOR (ERF), Jasmonic acid (JA), and IAA [47,49].…”