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The studies on the selective synthesis of dialkyl selenide compounds 1 were presented. Overcoming the complexity and difficulty of selenides (R-Se-R) and/or multiselenides (R-Se n -R; n ≥ 2), we aimed to optimize the reaction condition for the tolerable preparation of sodium selenide (Na 2 Se) by reducing Se with NaBH 4 , and then to achieve selective syntheses of dialkyl selenides 1 by subsequently treating the obtained sodium selenide with alkyl halides (RX). Consequently, various dialkyl selenides 1 were efficiently synthesized in good-to-moderate yields. The investigations on reaction pathways and solvent studies were also described.

The inter-subspecific crossing between indica and japonica subspecies in rice have been utilized to improve the yield potential of temperate rice. In this study, a comparative study of the genomic regions in the eight high-yielding varieties (HYVs) was conducted with those of the four non-HYVs. The Next-Generation Sequencing (NGS) mapping on the Nipponbare reference genome identified a total of 14 common genomic regions of japonica -originated alleles. Interestingly, the HYVs shared japonica -originated genomic regions on nine chromosomes, although they were developed through different breeding programs. A panel of 94 varieties was classified into four varietal groups with 38 single nucleotide polymorphism (SNP) markers from 38 genes residing in the japonica -originated genomic regions and 16 additional trait-specific SNPs. As expected, the japonica -originated genomic regions were only present in the japonica (JAP) and HYV groups, except for Chr4-1 and Chr4-2. The Wx gene, located within Chr6-1, was present in the HYV and JAP variety groups, while the yield-related genes were conserved as indica alleles in HYVs. The japonica -originated genomic regions and alleles shared by HYVs can be employed in molecular breeding programs to further develop the HYVs in temperate rice.

Chlorophyll breakdown is a vital catabolic process of leaf senescence as it allows the recycling of nitrogen and other nutrients. In the present study, we isolated rice senescence-induced receptor-like kinase ( OsSRLK ), whose transcription was upregulated in senescing rice leaves. The detached leaves of ossrlk mutant ( ossrlk ) contained more green pigment than those of the wild type (WT) during dark-induced senescence (DIS). HPLC and immunoblot assay revealed that degradation of chlorophyll and photosystem II proteins was repressed in ossrlk during DIS. Furthermore, ultrastructural analysis revealed that ossrlk leaves maintained the chloroplast structure with intact grana stacks during dark incubation; however, the retained green color and preserved chloroplast structures of ossrlk did not enhance the photosynthetic competence during age-dependent senescence in autumn. In ossrlk , the panicles per plant was increased and the spikelets per panicle were reduced, resulting in similar grain productivity between WT and ossrlk . By transcriptome analysis using RNA sequencing, genes related to phytohormone, senescence, and chlorophyll biogenesis were significantly altered in ossrlk compared to those in WT during DIS. Collectively, our findings indicate that OsSRLK may degrade chlorophyll by participating in a phytohormone-mediated pathway.