Chlorophyll (Chl) degradation is one of the most obvious signs of leaf senescence and fruit ripening. Stay-green (SGR) homologs that can remove magnesium from Chl a are the most important components in Chl degradation pathway in green plants. SGR homologs are not only universally involved in Chl breakdown during the senescence of green organs, but also play crucial roles in other organs during plant growth and development, such as fruit mature and nodule development. In this review, we focus on the diverse functions of SGR homologs in plant growth and development. A better understanding of SGR would be helpful for providing a theoretical basis for further illustrating the regulatory mechanism of SGR homologs.

Family-1 UDP-glycosyltransferases (UGTs) are the most common and functional glycosyltransferases in the plant world. UGT is closely related to plant growth and the response to abiotic stress. However, despite systematic research, our understanding of potato UGT genes is still unclear. In this study, we identified 174 potato UGT proteins based on their conserved plant secondary product glycosyltransferase (PSPG) motifs. Phylogenetic analyses were used to compare these proteins with Arabidopsis UGTs and other plant UGTs, and it was found that they could be clustered into 18 distinct groups. Patterns of intron gain/loss and intron phases within potato UGTs revealed highly conserved intron insertion events. The promoter cis-elements of these 174 UGT genes were systematically investigated. The promoter regions of these UGT genes are known to contain various classes of cis-acting compounds. These include elements that are light-responsive, phytohormone-responsive, and stress-responsive. Transcriptome data analysis established that 25, 10, 6, and 4 of these 174 UGT genes were specifically expressed in leaves, roots, stolons, and young tubers, respectively. The mannitol-treated transcriptomic data showed thirty-eight UGT genes were significantly upregulated. The quantitative real-time PCR results showed that the four genes were all responsive to osmotic stress under a 10% PEG6000 treatment. The results of our study provide a basis for clarifying the molecular mechanism of potato osmotic stress resistance and better understanding its function in the future.

Potato stolon research has emphasized stolon-tip tuberization, leaving the transition of basal axillary buds into subterranean stolons poorly characterized. Using cv. Désirée, we characterized this transition at IS0 immediately before soil covering and at 5, 7, 9, and 11 d thereafter (IS5, IS7, IS9, and IS11) by morphological, histological, and transcriptomic analyses. At IS5, external morphology changed little, although internal tissue reorganization was evident. During IS7–IS9, buds progressively reoriented, enlarged basally, and established a subterranean lateral axis. By IS11, white stolons had formed and entered post-initiation elongation without visible stolon-tip swelling. PCA separated IS0 and IS11 from the intermediate stages, and adjacent-stage differential expression identified the largest DEG sets in IS0–IS5 and IS9–IS11. Direction-resolved GO and KEGG enrichment distinguished successive transitions: early oxidative/defense and phenylpropanoid-related categories; intermediate changes in transport, photosynthesis, redox metabolism, and cytoskeletal organization; and later enrichment of translation-, proteasome-, and cell-division-related categories. Mfuzz clustering provided a complementary overview of broad temporal trajectories, including IS5-associated C6, distinct C3 and C5 patterns during initiation, and IS11-associated C2. RT-qPCR profiles of StBRC1b, StWUS, StWOX5, StCCD8, StSP6A, and StSP3D were broadly consistent with the RNA-Seq trends. These results establish a time-resolved framework for soil-covering-induced stolon initiation and subsequent elongation.