Comprehensive analysis of NAC transcription factors and their expression during fruit spine development in cucumber (Cucumis sativus L.)

The cucumber(Cucumis sativus L.)is an important vegetable crop worldwide,and fruit trichomes or spines are an important trait for external fruit quality.The mechanisms underlying spine formation are not well understood,but the plant-specific NAC family of transcription factors may play important roles in fruit spine initiation and development.In this study,we conducted a genome-wide survey and identified 91 NAC gene homologs in the cucumber genome.Clustering analysis classified these genes into six subfamilies;each contained a varying number of NAC family members with a similar intron–exon structure and conserved motifs.Quantitative real-time PCR analysis revealed tissue-specific expression patterns of these genes,including 10 and 12 that exhibited preferential expression in the stem and fruit,respectively.Thirteen of the 91 NAC genes showed higher expression in the wild-type plant than in its near-isogenic trichome mutant,suggesting their important roles in fruit spine development.Exogenous application of four plant hormones promoted spine formation and increased spine density on the cucumber fruits;several NAC genes showed differential expression over time in response to phytohormone treatments on cucumber fruit,implying their essential roles in fruit-trichome development.Among the NAC genes identified,12 were found to be targets of 13 known cucumber micro-RNAs.Collectively,these findings provide a useful resource for further analysis of the interactions between NAC genes and genes underlying trichome organogenesis and development during fruit spine development in cucumber.

嫁接诱导对黄瓜部分农艺性状的影响

为探究黄瓜中是否存在嫁接诱导农艺性状变异现象,通过选用主要农艺性状存在明显差异的多份黄瓜高代自交系进行相互砧穗嫁接,对不同嫁接处理接穗G1代的主要农艺性状进行了对比分析。结果表明,嫁接处理2024/3297与自根嫁接处理2024/2024相比,接穗G1代雌花数量、雌花节位、F基因表达量显著减少;对接穗G1代果实长度进行对比分析,发现砧穗嫁接与对应自根嫁接处理相比果实长度发生变化。然而,对接穗G1代果实横径和果皮颜色进行对比分析,砧穗嫁接与自根嫁接处理之间不存在显著差异。黄瓜中存在嫁接诱导接穗后代部分农艺性状出现变化的现象。