Xinyang Maojian (XYMJ) tea is one of the world’s most popular green teas; the development of new sprouts directly affects the yield and quality of tea products, especially for XYMJ, which has hairy tips. Here, we used transcriptome and small RNA sequencing to identify mRNAs and miRNAs, respectively, involved in regulating leaf development in different plant tissues (bud, leaf, and stem). We identified a total of 381 conserved miRNAs. Given that no genomic data for XYMJ green tea are available, we compared the sequencing data for XYMJ green tea with genomic data from a closely related species (Tieguanyin) and the Camellia sinensis var. sinensis database; we identified a total of 506 and 485 novel miRNAs, respectively. We also identified 11 sequence-identical novel miRNAs in the tissues of XYMJ tea plants. Correlation analyses revealed 97 miRNA–mRNA pairs involved in leaf growth and development; the csn-miR319-2/csnTCP2 and miR159–csnMYB modules were found to be involved in leaf development in XYMJ green tea. Quantitative real-time PCR was used to validate the expression levels of the miRNAs and mRNAs. The miRNAs and target genes identified in this study might shed new light on the molecular mechanisms underlying the regulation of leaf development in tea plants.

Somatic embryogenesis receptor-like kinases (SERKs), a subfamily of receptor-like kinases, play important roles in response to abiotic stresses in addition to apomictic reproductive development in numerous plant species. The purpose of the present work was to determine if an ortholog of the SERK gene is present in the Diospyros lotus genome, isolate it and analyze its expression during embryogeny and abiotic stress. An ortholog of the SERK gene was isolated from the D. lotus genome, and designated as DlSERK1. The physical and chemical properties, protein structure, and evolutionary relationship of the DlSERK1 protein were analyzed by bioinformatics methods, and the expression of DlSERK1 gene during embryonic development and under low-temperature, salt, and drought stresses was examined through real-time quantitative PCR analysis. DlSERK1 contained 1,881 bp open reading frame encoding 626 amino acids, with a molecular mass of 69.18 kDa and pI of 5.34. DlSERK1 had strong hydrophilic property, signal peptide cleavage sites, and two transmembrane regions, indicating that DlSERK1 is a secretory protein. The secondary structure of DlSERK1 was consistent with the tertiary structure, both of which were dominated by random curls and alpha-helices. DlSERK1 had the typical structure of SERK proteins, and harbored multiple phosphorylation and glycosylation sites. Quantitative analysis showed that DlSERK1 was expressed during the embryonic development period, and the highest expression level was at 10 days post-flowering. The DlSERK1 expression level was down-regulated under low-temperature stress and up-regulated under drought and salt stresses. Our study showed that DlSERK1 was expressed in embryo development and could respond to low-temperature, drought, and salt stresses, which lays a foundation for further research on the function of SERK1 in the apomixis growth and development of environmental adaptation in D. lotus.

To investigate the inheritance and expression of exogenous cowpea trypsin inhibitor (CpTI) and neomycin phosphotransferase II (nptII) genes in the progenies of transgenic apples (Malus domestica Borkh.), hybrid (F1) fruits and seeds were obtained using transgenic Gala and non-transgenic Fuji for cross and reciprocal cross experiments. Transgenic apple hybrid F1 plants were obtained using the established apple embryo culture system. The law of segregation of nptII in the hybrid progeny was studied through successive selections under high-level kanamycin pressure. The genetic linkage between CpTI and nptII was tested by PCR analysis. The effects of exogenous genes on transgenic apple fruits were measured by nptII enzyme activity, fruit weight, fruit shape index, fruit hardness, soluble solids content, acid content, and other related indicators in the transgenic Gala fruit. The kanamycin resistance test in F1 plantlets 1:1 Mendelian ratio of kanamycin resistance to non-resistance . Thus, the nptII marker gene, a dominant heterozygous gene, passed onto the progenies through sexual hybridization. PCR analysis also showed that CpTI was closely linked to nptII . The activity of nptII enzyme was detected in most transgenic apples, but the intensity of nptII enzyme activity in different fruits was different.. Transgenic Gala fruit and the control fruit were oblate or nearly round, with the fruit shape index ranging between 0.83 and 0.90. Acid content of a transgenic fruit was not significantly different compared to the control. Fruit hardness and soluble solids content were significantly lower compared to the control. The results provide a reference for further studies on the genetic characteristics of transgenic apples and the utilization of transgenic products. Bangladesh J. Bot. 53(4): 1043-1053, 2024 (December)