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IntroductionSoil salinization is a serious abiotic stress for grapevines. The rhizosphere microbiota of plants can help counter the negative effects caused by salt stress, but the distinction between rhizosphere microbes of salt-tolerant and salt-sensitive varieties remains unclear.MethodsThis study employed metagenomic sequencing to explore the rhizosphere microbial community of grapevine rootstocks 101-14 (salt tolerant) and 5BB (salt sensitive) with or without salt stress.Results and DiscussionCompared to the control (treated with ddH2O), salt stress induced greater changes in the rhizosphere microbiota of 101-14 than in that of 5BB. The relative abundances of more plant growth-promoting bacteria, including Planctomycetes, Bacteroidetes, Verrucomicrobia, Cyanobacteria, Gemmatimonadetes, Chloroflexi, and Firmicutes, were increased in 101-14 under salt stress, whereas only the relative abundances of four phyla (Actinobacteria, Gemmatimonadetes, Chloroflexi, and Cyanobacteria) were increased in 5BB under salt stress while those of three phyla (Acidobacteria, Verrucomicrobia, and Firmicutes) were depleted. The differentially enriched functions (KEGG level 2) in 101-14 were mainly associated with pathways related to cell motility; folding, sorting, and degradation functions; glycan biosynthesis and metabolism; xenobiotics biodegradation and metabolism; and metabolism of cofactors and vitamins, whereas only the translation function was differentially enriched in 5BB. Under salt stress, the rhizosphere microbiota functions of 101-14 and 5BB differed greatly, especially pathways related to metabolism. Further analysis revealed that pathways associated with sulfur and glutathione metabolism as well as bacterial chemotaxis were uniquely enriched in 101-14 under salt stress and therefore might play vital roles in the mitigation of salt stress on grapevines. In addition, the abundance of various sulfur cycle-related genes, including genes involved in assimilatory sulfate reduction (cysNC, cysQ, sat, and sir), sulfur reduction (fsr), SOX systems (soxB), sulfur oxidation (sqr), organic sulfur transformation (tpa, mdh, gdh, and betC), increased significantly in 101-14 after treatment with NaCl; these genes might mitigate the harmful effects of salt on grapevine. In short, the study findings indicate that both the composition and functions of the rhizosphere microbial community contribute to the enhanced tolerance of some grapevines to salt stress.

The ensemble technique is considered to be an effective approach in enhancing the model capacity of intra-seasonal climate change. Since El Niño-Southern Oscillation is one of the critical modes of interannual variability in the tropical Pacific, an appropriate ensemble technique may help minimize model bias in ENSO forecast. This research includes a modified stochastically perturbed parameterization tendencies scheme in the Community Earth System Model to investigate its impact on ENSO prediction. This revised scheme uses independent noise patterns to perturb the tendencies from different physical parameterizations. In the original scheme, only the same noise is employed. The result suggests that the altered approach is in a position to further reduce sea surface temperatures and gain more skill in uncertainty estimation compared to the original one. ENSO’s amplitude is improved especially of its warm phase El Niño, but there is a limited improvement in its spatial structure. The modified scheme also ameliorated the variability of ENSO by increasing the magnitude toward observation. The power spectrum exhibits an increased representation. Besides those findings, we notice that simple ensemble mean may not be able to represent the climate status as it smoothes out some useful signals.