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

Abstract 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 dark-treated grape leaves. The information will advance our understanding of function-related genes in grape exposed to shade management / dark stress.