Under high temperature, PIF4 promoted hypocotyl elongation of Arabidopsis by regulating auxin synthesis and up regulate the expression of SAUR in hypocotyls. Previous studies found that auxin participates in many important processes by promoting cell expansion, including hypocotyl elongation, leaf growth, phototropic growth, apical hook, and hair development. It is this characteristic of auxin that allowed its discovery. One of the functions of auxin is to stimulate cell expansion. Īuxin is an important hormone in plants, which plays a key role in plant growth and development. Entering the second rapid growth period, the growth was completely dependent on cell expansion. At 4–6 weeks after anthesis, grapes entered the slow growth phase, the cell expansion rate decreased, and cell division stopped. During the first rapid growth period of grape berry, cell division and cell expansion occurred simultaneously. Therefore, the fruit size of Arabidopsis mainly depends on cell expansion. It was found that the valve cell had a higher rate of cell expansion, and no cell division was detected. The growth dynamics of Arabidopsis fruit were observed, and cell expansion and cell division data were collected for quantitative analysis. In Arabidopsis, the expansion of the valve determines the fruit size. The cell diameter of some tomato varieties can reach 0.5 mm, and diameter plays an important role in the final size of the fruit.
Cell expansion occupies most stages of fruit development. Subsequently, the growth of the fruit mainly depends on cell expansion until the fruit matures, and the number of cells remains almost the same. The transition from cell division to cell expansion is completed in 7–14 days after anthesis. Two days after fertilization, the tomato ovules undergo rapid cell division to form a fleshy peel, which envelops the placenta and seeds to form young fruits. In tomato, cell expansion contributes the most to the final berry size. It can directly and effectively increase the berry volume and determine the final berry size. The activity of cell division determines the final number of cells, but cell expansion is crucial. The berry size is determined by the number and volume of cells that make up the berry. As the demand for berries continues to grow, modern breeding took berry size as the main target trait. This genome-wide study provides a systematic analysis of grape SAUR gene family, further understanding the potential functions of candidate genes, and provides a new idea for grape breeding.Īs the main target trait of long-term plant domestication, berry size plays an important role in improving the quality and yield of grape. Finally, the member related to grape berry size in SAUR gene family were screened. Subsequently, we conducted a comprehensive and systematic analysis on the SAUR gene family by analyzing distribution of key amino acid residues in the domain, structural features, conserved motifs, and protein interaction network, and combined with the heterologous expression in Arabidopsis and tomato. We identified 60 SAUR members in the grape genome and divided them into 12 subfamilies based on phylogenetic analysis.
However, the SAUR gene family’s function in berry size of grape has not been studied systematically. Berry size is one of the important factors that determine grape quality. As the largest family of auxin early response genes, SAUR (small auxin upregulated RNA) plays an important role in the growth and development of plants. Cultivating larger berry varieties can be an effective way to solve this problem. However, the small size of the berry limits its yield. Grape ( Vitis vinifera) is an important horticultural crop that can be used to make juice and wine.