Salt injury, as an abiotic stress factor, seriously affects the quality and yield of crops. This study was conducted by analyzing alternative splicing in the control (CK), δ-aminolevulinic acid (ALA), NaCl, and ALA + NaCl treatments of wild jujube (Zizyphus spinosus (Bunge)Hu) using RNA-seq. It was found that the unique differential alternative splicing is closely related to the alleviation of salt stress and the analyzed intermediates of chlorophyll synthesis and chlorophyll content in the leaves. The results showed that the content and synthesis of chlorophyll were reduced and disrupted in wild jujube leaves under NaCl stress, and the exogenous spraying of ALA could alleviate the effect of NaCl stress on the content of chlorophyll. RNA-seq indicated that the alternative splicing of genes was dominated by exon skipping in all the experimental treatments. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses revealed that the CK and ALA + NaCl comparison groups were primarily enriched in porphyrin and chlorophyll metabolism, chloroplast, and energy metabolism pathways. It is hypothesized that ALA treatment can alleviate the effects of salt stress on chlorophyll by altering the alternative splicing of genes related to photosynthesis, chlorophyll metabolism, and energy metabolism in wild jujube. In addition, the verification of alternative splicing genes related to chlorophyll metabolism in wild jujube revealed that treatment with ALA significantly upregulated the expression of HEMH, UROIII, and ChlD genes in the leaves under salt stress and increased the content of the chlorophyll biosynthetic intermediates endogenous ALA, porphobilinogen, protoporphyrin IX, Mg-protoporphyrin IX, and protochlorophyllide, which served to alleviate the effects of NaCl stress on chlorophyll in wild jujube.

In recent years, Colomerus vitis has caused serious economic losses due to reduced grape production in Xinjiang (northwest China). Several rootstock varieties have been reported to improve the resistance of Cabernet Sauvignon to Colomerus vitis. This study explored the influence of Cabernet Sauvignon with different rootstocks on the resistance to Colomerus vitis. In particular, Cabernet Sauvignon/Cabernet Sauvignon (CS/CS) was selected as the control, and Cabernet Sauvignon grafted with five resistant rootstocks (3309C, 1103P, 140R, SO4, and 5C) was employed as the treatment. The infestation rate and injury index of Colomerus vitis to grapevines was investigated, and insect-resistant types of grapevines with different rootstocks were determined. The resveratrol (Res) content, the gene expression of resveratrol synthase (RS), and the activities of peroxidase (POD), polyphenol oxidase (PPO), catalase (CAT), and superoxide dismutase (SOD) in the leaves of each rootstock grapevine were measured. The activity of the four enzymes and the content of Res were negatively correlated with the injury index. The results revealed the ability of the rootstock to improve the resistance of grapevines to Colomerus vitis by increasing the enzyme activity or Res content. In particular, 140R, SO4, and 5C rootstocks can be employed as rootstocks of the ‘Cabernet Sauvignon’ grapevine with resistance to Colomerus vitis. The contents of Res and the four resistance enzymes studied here can be used as indexes to evaluate the insect resistance of rootstock–scion combinations.

Different rootstocks for grapes can significantly affect fruit color and quality, possibly by affecting hormone contents, related genetic pathways, and fruit coloring mechanisms in peels. ‘Cabernet Sauvignon’ were grafted to ‘5BB’, ‘SO4’, ‘140R’, ‘CS’, ‘3309M’ and ‘Vitis riparia’ rootstocks, with self-rooting seedlings as the control (CS/CS), and sampled from the early stage of color transformation to the ripening stage. The effects of rootstock on the contents of gibberellin (GA3), auxin (IAA), and abscisic acid (ABA) in grape peels were determined alongside the expression levels of eight anthocyanin synthesis related genes using real-time fluorescence quantitative PCR methods. The rootstock cultivars exhibited accelerated fruit color change, and the CS/140R cultivar had much greater color change than the control group in the same period. With the development of fruit, the IAA and GA3 contents in the peels of different rootstock combinations showed trends of increasing initially, then decreasing, while the ABA content decreased initially and then increased. During the fruit color change period (28 July), the various ‘Cabernet Sauvignon’ rootstock combinations exhibited varying degrees of increases in GA3, ABA, and IAA contents; correlation analysis showed that, at the start of veraison, the expression levels of the anthocyanin synthesis-related genes VvCHS, VvDFR, and VvUFGT had strong positive correlations with hormone contents, which indicated they are key genes involved in the endogenous hormone responsive anthocyanin biosynthesis pathway. The results of this study showed that rootstock grafting regulates the fruit coloring process by influencing the metabolism level of peel hormones in the ‘Cabernet Sauvignon’ grape.