Dark inhibits leaf size by controlling carbohydrate and auxin catabolism in grape

Shading/dark stress of leaves is a common phenomenon during cultivation of grape. The morphological and photosynthetic characteristics of grape leaves are considerably affected under shading. However, little is known about the underlying mechanisms of shade/dark inhibition effect on grape leaf area at the transcriptome level. We conducted the transcriptome of dark-treated grape leaves using RNA-Seq technology. A total of 24,920 transcripts were obtained, from which 1943 differentially expressed genes (DEGs) were both recorded in the comparisons of 12 h dark vs 12 h light and 24 h dark vs 24 h light. Gene ontology enrichment analyses revealed that most of these DEGs enriched in photosynthesis and carbohydrate biosynthesis was down-regulated, but sucrose catabolism genes and cell wall degradation were up-regulated in the dark, which resulted in accumulate less carbohydrates. Furthermore, genes involved in auxin catabolism and transport were induced after 12 h of dark treatment contribute to lower indole-3-acetic acid (IAA) content. Our datas suggest that the lower auxin content and insufficient carbohydrate supply on cell division and expansion contribute to smaller size of darktreated grape leaves. The information will advance our understanding of function-related genes in grape exposed to shade management / dark stress.

Automated summary

RNA-Seq analysis of dark-treated grape leaves revealed that shading/dark stress affects sucrose metabolism and cell wall degradation, resulting in smaller leaf size. Additionally, lower auxin content contributes to the inhibition of grape leaves under dark conditions.