Yong-Juan Cheng

Long-term clean tillage in apple orchards on the Loess Plateau has degraded soil properties and diminished fruit quality, highlighting the urgent need for sustainable cover cropping strategies. In a two-year field experiment (two consecutive growing seasons), eight green manure species (annual ryegrass, perennial ryegrass, white clover, smooth vetch, common vetch, rapeseed, hairy vetch, and cocksfoot) were compared with a clean-tillage control. Each treatment was replicated three times, and each plot was 100 m². Soil physicochemical properties, microbial communities (16S rRNA and ITS amplicon sequencing), and fruit quality parameters were systematically assessed. All grass treatments significantly lowered soil pH and increased soil organic matter and total nitrogen, phosphorus, and potassium contents. Hairy vetch (T7) produced the highest soil organic matter (25.86 g kg⁻¹) and total nitrogen (1.43 g kg⁻¹), while rapeseed (T6) reduced pH most markedly (4.28%). White clover (T3) enhanced bacterial and fungal alpha-diversity and enriched beneficial genera (Sphingomonas, Lysobacter, Mortierella, Chaetomium). However, functional predictions based on 16S/ITS data using FAPROTAX and Tax4Fun (PICRUSt-type predictive tools) suggested a potential increase in chemoorganoheterotrophy and saprotrophy; these predicted functions should be interpreted as hypothesis-generating rather than as direct evidence of microbial function. Common vetch (T5) increased soluble sugar content by 28.1%, and cocksfoot (T8) decreased titratable acidity by 30.8%. The comprehensive analysis indicates that hairy vetch and white clover as the most effective species for improving soil fertility, microbial diversity, and fruit quality. We therefore recommend these two legumes as optimal cover crops for sustainable orchard floor management in rain-fed semi-arid regions of the Loess Plateau.

SNARE proteins (soluble N-ethylmaleimide-sensitive factor attachment protein receptors) play a key role in mediating a variety of plant biological processes. Currently, the function of the SNARE gene family in phytohormonal and abiotic stress treatments in grapevine is currently unknown, making it worthwhile to characterize and analyze the function and expression of this family in grapevine. In the present study, 52 VvSNARE genes were identified and predominantly distributed on 18 chromosomes. Secondary structures showed that the VvSNARE genes family irregular random coils and α-helices. The promoter regions of the VvSNARE genes were enriched for light-, abiotic-stress-, and hormone-responsive elements. Intraspecific collinearity analysis identified 10 pairs collinear genes within the VvSNARE family and unveiled a greater number of collinear genes between grapevine and apple, as well as Arabidopsis thaliana, but less associations with Oryza sativa. Quantitative real-time PCR (qRT-PCR) analyses showed that the VvSNARE genes have response to treatments with ABA, NaCl, PEG, and 4 °C. Notably, VvSNARE2, VvSNARE14, VvSNARE15, and VvSNARE17 showed up-regulation in response to ABA treatment. VvSNARE2, VvSNARE15, VvSNARE18, VvSNARE19, VvSNARE20, VvSNARE24, VvSNARE25, and VvSNARE29 exhibited significant up-regulation when exposed to NaCl treatment. The PEG treatment led to significant down-regulation of VvSNARE1, VvSNARE8, VvSNARE23, VvSNARE25, VvSNARE26, VvSNARE31, and VvSNARE49 gene expression. The expression levels of VvSNARE37, VvSNARE44, and VvSNARE46 were significantly enhanced after exposure to 4 °C treatment. Furthermore, subcellular localization assays certified that VvSNARE37, VvSNARE44, and VvSNARE46 were specifically localized at the cell membrane. Overall, this study showed the critical role of the VvSNARE genes family in the abiotic stress response of grapevines, thereby providing novel candidate genes such as VvSNARE37, VvSNARE44, and VvSNARE46 for further exploration in grapevine stress tolerance research.