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Ethylene plays an important role in regulating the development and ripening of fruits, and 1-aminocyclopropane carboxylic acid synthase is the key rate-limiting enzyme in ethylene synthesis pathway. In this study, eight PpACS genes were identified from the peach genome [Prunus persica (L.) Batsch], and their phylogeny, gene structures, promoter motifs and expression patterns were analyzed. The PpACS genes could be divided into four types, and the genes with similar structures and motif distribution clustered together. Identification of the cis-elements in the promoters revealed that the PpACS genes may respond to various hormones. Furthermore, expression analysis showed that five (PpACS1, PpACS5, PpACS6, PpACS7 and PpACS8) of the eight PpACS genes were expressed at different stages during peach fruit development. Among them, PpACS1 was highly expressed at the ripening stage and induced by ethylene. The expression peaks of PpACS5, PpACS6, PpACS7 and PpACS8 during the transition from first exponential growth to pit hardening (S1 to S2) indicated a potential function of ethylene during this important transition. Taken together, these results provide valuable information for future investigation into the functions of the PpACS genes during peach fruit development and ripening.

Jujube witches' broom (JWB) disease, referred to as 'Zaofeng' disease in Chinese, is associated with the JWB phytoplasma ('Candidatus Phytoplasma ziziphi') and causes heavy losses in the jujube industry. JWB disease has been recorded since the 1950s. Diseased trees have symptoms such as shoot proliferation and leaf-like flowers. The JWB phytoplasma is assigned to the 16SrV group, subgroup 16SrV-B, according to 16S rRNA gene sequence. The JWB phytoplasma is transmitted by leafhoppers and can infect a few plants other than jujube. Infection with phytoplasma affects biochemical and physiological process, altering the expression of genes encoding some transcription factors and functional genes, mainly involved in biotic stress response. The genome of JWB phytoplasma 'nky' strain has been sequenced and consists of 750,803 bp within one circular chromosome that encodes 694 protein-coding genes. The pathogenic mechanisms of a few JWB phytoplasma effectors have been investigated. The presence of JWB phytoplasma has been detected through symptoms observation, ELISA, DAPI staining and PCR, but new techniques, such as LAMP and CRISPR/Cas-12 based visual assay, have recently been developed. Some resistant jujube cultivars have been selected by infection screening. Although treatment with tetracycline antibiotics is effective, comprehensive control measures, including orchard management and sanitary measures, are needed for disease control. Further studies are needed in development of JWB phytoplasma culture method, expansion of genomic information, and phytoplasma effectors, resistance-related gene identification and resistant genotype developing.

Ethylene plays an important role in grape ripening, acting through ethylene response factors (ERFs) that are downstream of ethylene signaling pathways, yet little else is known about these molecular mechanisms. In our study, we demonstrate that ethylene treatment promotes grape ripening and that the transcription factor VvERF75 shows increased expression during grape ripening. VvERF75 was found to contain a conserved AP2/ERF domain, to be a member of the ERF IXa subfamily, and to localize to the nucleus and to have transactivation activity in yeast. Our in vitro assays showed that VvERF75 can positively regulate expression of pheophorbide a oxygenase (VvPAO1) and 1-aminocyclopropane-1-carboxylic acid synthase (VvACS5) by binding to DRE motifs in their promoters. Overexpression of VvERF75 in tomato increased ethylene production and resulted in dwarfed plants, early flowering and fruit ripening, increased SlPAO and SlACS transcript levels, and decreased chlorophyll content. In general, our study revealed that VvERF75 may regulate fruit ripening by promoting ethylene biosynthesis and chlorophyll degradation, a discovery that lays a foundation for deciphering the molecular mechanisms of grape ripening.

Anthocyanins, a categories of metabolites derived from flavonoid biosynthesis pathway, are responsible for the red color of peach. Anthocyanin metabolism is modulated by a complicated regulatory network. In this study, our results demonstrated that PpNAC25 was a component of anthocyanin regulatory network in peach. PpNAC25 showed a closed relationship with the well-known ripening-related gene NOR (no-ripening) and was highly expressed in peach fruit. Overexpression of PpNAC25 in poplar resulted in a redder shoot tips compared with EV control. PpNAC25 overexpression upregulated the anthocyanin biosynthetic and transportation genes in transcript levels and then increased anthocyanin contents. In Y1H and Luc/Ren assay, PpNAC25 bound to the promoter of the anthocyanin-activator PpMYB10.1 and PpMYB10.2 and activated its transcript. Moreover, PpNAC25 formed a heterodimer with PpNAC1, an anthocyanin-regulator. Our researches provide evidence that PpNAC25 may be a positive regulator of anthocyanin biosynthesis in peach fruit.