RESUMEN

Atomic engineering of the basal plane active sites in MoS2 holds great promise to boost the electrocatalytic activity for hydrogen evolution reactions (HER), yet the performance optimization and mechanism exploration are still not satisfactory. Herein, we proposed a dual-plasma engineering strategy to implant Ti and N heteroatoms into the basal plane of MoS2 supported by Ni3S2 nanorods on nickel foam (MSNF) for efficient electrocatalysis of HER. Owing to the low formation energy of Ti dopants in MoS2 and the extra charge carriers introduced by N dopants, the optimally codoped samples N1.0@Ti500-MSNF demonstrate significant morphology changes from nanorods to urchin-like nanospheres with the surface active areas increased by seven-fold, as well as enhanced electrical conductivity in comparison with the nondoped counterparts. The HER performance of N1.0@Ti500-MSNF is comparable with the Pt-based catalyst: overpotential of 26 mV at 20 mA cm-2, Tafel slope of 35.6 mV dec-1, and long-term stability over 50 h. First-principles calculation reveals that N doping accelerates the dissociation of water molecules while Ti doping activates the adjacent S sites for hydrogen adsorption by lowering the Gibbs free energy, resulting in excellent HER activity. This work thus provides an effective strategy for basal plane engineering of MoS2 heterostructures toward high-performance HER and sustainable energy supply at reasonable costs.

RESUMEN

Chlorophyll biosynthesis and chloroplast development are essential for photosynthesis and plant growth. Gossypium arboreum, a valuable source of genetic variation for cotton improvement, remains poorly studied for the mechanisms regulating chlorophyll biosynthesis and chloroplast development. Here we created a G. arboreum etiolated leaf and stuntedness (els) mutant that displayed a distinct yellow color of leaves, bracts and stems throughout the whole growth, where chlorophyll accumulation in leaves was reduced and chloroplast development was delayed. The GaCHLH gene, which encodes the H subunit of magnesium chelatase (Mg-chelatase), was screened by MutMap and KASP analysis. Compared to GaCHLH, the gene Gachlh of the mutant had a single nucleotide transition (G to A) at 1549 bp, which causes the substitution of a glycine (G) by a serine (S) at the 517th amino acid, resulting in an abnormal secondary structure of the Gachlh protein. GaCHLH-silenced SXY1 and ZM24 plants exhibited a lower GaCHLH expression level, a lower chlorophyll content, and the yellow-leaf phenotype. Gachlh expression affected the expression of key genes in the tetrapyrrole pathway. GaCHLH and Gachlh were located in the chloroplasts and that alteration of the mutation site did not affect the final target position. The BiFC assay result indicated that Gachlh could not bind to GaCHLD properly, which prevented the assembly of Mg-chelatase and thus led to the failure of chlorophyll synthesis. In this study, the Gachlh gene of G. arboreum els was finely localized and identified for the first time, providing new insights into the chlorophyll biosynthesis pathway in cotton.

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RESUMEN

D-Lactate is oxidized by two classes of D-lactate dehydrogenase (D-LDH), namely, NAD-dependent and NAD-independent D-LDHs. Little is known about the characteristics and biological functions of D-LDHs in rice. In this study, a functional NAD-independent D-LDH (LOC_Os07g06890) was identified in rice, as a result of alternative splicing events. Characterization of the expression profile, subcellular localization, and enzymatic properties of the functional OsD-LDH revealed that it is a mitochondrial cytochrome-c-dependent D-LDH with high affinity and catalytic efficiency. Functional analysis of OsD-LDH RNAi transgenic rice demonstrated that OsD-LDH participates in methylglyoxal metabolism by affecting the activity of the glyoxalase system and aldo-keto reductases. Under methylglyoxal treatment, silencing of OsD-LDH in rice resulted in the accumulation of methylglyoxal and D-lactate, the decrease of reduced glutathione in leaves, and ultimately severe growth inhibition. Moreover, the detached leaves of OsD-LDH RNAi plants were more sensitive to salt stress. However, the silencing of OsD-LDH did not affect the growth under photorespiration conditions. Our results provide new insights into the role of NAD-independent D-LDHs in rice.

RESUMEN

Rice leaffolder, Cnaphalocrocis medinalis (Guenée), is a destructive and widespread pest on rice. In this study, 20 microsatellite markers were isolated and characterized from C. medinalis partial genomic libraries using the method of fast isolation by AFLP of sequence containing repeats. Of these markers, 18 markers displayed polymorphisms. Polymorphisms were evaluated in 48 individuals from two natural populations. The number of alleles per locus ranged from 2 to 15, and the expected and observed heterozygosities ranged from 0.324 to 0.934 and from 0.304 to 0.917, respectively. Cross-species amplification was also performed to test the transferability of the 20 microsatellite markers and a moderate level of cross amplication was observed across the three species of Pyralididae (26.67 %). These microsatellite loci would facilitate the future study on population genetics and molecular genetics of rice leaffolder and would also be useful for study in Chilo suppressalis, Scirpophaga incertulas and Pyrausta nubilalis.

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