Intron Retention Fine-Tunes the Resistance of the Rice Mutant pls4 to Rice Sheath Blight(Rhizotonia solani AG I.1a)

OsPLS4 encodes aβ-ketoacyl carrier protein reductase(KAR).The role of OsPLS4 in rice sheath blight(Rhizoctonia solani)remains unclear.Our preliminary studies showed that premature leaf senescence mutants(pls4)were highly susceptive to sheath blight in the early stage of rice development.To explore the role of this gene in the development of rice sheath blight,the transcriptome profiles of the rice pls4 mutant and wild type were compared by RNA-seq.The results revealed 2,569 differentially expressed genes(DEGs).The down-regulated genes were significantly enriched in the defense response-related biological processes.These down-regulated genes included the chitinase genes and WRKY genes,which were significantly changed in pls4 mutants.Furthermore,467 genes induced significant alternative splicing(AS)events.Among them,intron retention(IR)affected gene expression levels and functions of the vitamin B6(VB6)metabolism pathway related to sheath blight.This result suggests that IR plays an important role in the sheath blight resistance of mutant pls4.Together,these results indicate that pls4 could be involved in the biological process of sheath blight via DEGs and the fine-tuning of IR.The present study provides a molecular basis for further investigation of the resistance of rice to sheath blight.

Mercury in soil,vegetable and human hair in a typical mining area in China:Implication for human exposure

Concentrations of total mercury（T-Hg） and methylmercury（MeHg） in soil, vegetables, and human hair were measured in a mercury mining area in central China. T-Hg and MeHg concentrations in soil ranged from 1.53 to 1054.97 mg/kg and 0.88 to 46.52 μg/kg, respectively.T-Hg concentrations was correlated with total organic carbon（TOC） content（R^2= 0.50, p〈0.01）and pH values（R^2= 0.21, p〈0.05）. A significant linear relationship was observed between MeHg concentrations and the abundance of sulfate-reducing bacteria（SRB）（R^2= 0.39, p〈0.05） in soil.Soil incubation experiments amended with specific microbial stimulants and inhibitors showed that Hg methylation was derived from SRB activity. T-Hg and MeHg concentrations in vegetables were 24.79 – 781.02 μg/kg and 0.01 – 0.18 μg/kg, respectively; levels in the edible parts were significantly higher than in the roots（T-Hg： p〈0.05; MeHg： p〈0.01）. Hg species concentrations in rhizosphere soil were positively correlated to those in vegetables（p〈0.01）, indicating that soil was an important source of Hg in vegetables. Risk assessment indicated that the consumption of vegetables could result in higher probable daily intake（PDI） of T-Hg than the provisional tolerable daily intake（PTDI） for both adults and children. In contrast, the PDI of MeHg was lower than the reference dose. T-Hg and MeHg concentrations in hair samples ranged from 1.57 to 12.61 mg/kg and 0.04 to 0.94 mg/kg, respectively, and MeHg concentration in hair positively related to PDI of MeHg via vegetable consumption（R^2= 0.39, p〈0.05）, suggesting that vegetable may pose health risk to local residents.

Alternative Polyadenylation： Methods, Findings, and Impacts

Alternative polyadenylation （APA）, a phenomenon that RNA molecules with different 3＇ ends originate from distinct polyadenylation sites of a single gene, is emerging as a mechanism widely used to regulate gene expression. In the present review, we first summarized various methods prevalently adopted in APA study, mainly focused on the next-generation sequencing （NGS）-based techniques specially designed for APA identification, the related bioinformatics methods, and the strategies for APA study in single ceils. Then we summarized the main findings and advances so far based on these methods, including the preferences of alternative polyA （pA） site, the biological processes involved, and the corresponding consequences. We especially categorized the APA changes discovered so far and discussed their potential functions under given conditions, along with the possible underlying molecular mechanisms. With more in-depth studies on extensive samples, more signatures and functions of APA will be revealed, and its diverse roles will gradually heave in sight.