ABSTRACT
Alniaria alnifolia (Siebold and Zucc.) Rushforth, 2018 (alternative name: Sorbus alnifolia) belongs to the genus Alniaria of the family Rosaceae and is widely distributed in northern China, Korea, and Japan. It is an essential resource used in the construction, pharmaceuticals, and food industries. It is also used to treat various diseases, such as fever, hyperglycemia, rash, asthma, bronchitis, constipation, leprosy, anemia, and other skin ailments. In this study, we sequenced a sample of A. alnifolia and determined its complete chloroplast genome. The chloroplast genome of A. alnifolia has a circular structure with a length of 159,855 bp, which includes a small single-copy region (19,409 bp), a large single-copy region (87,628 bp), and two inverted repeats (26,409 bp). The sequence had 130 genes, including 85 protein-coding genes, eight rRNA genes, and 37 tRNA genes, and the overall GC content was 36.6%. The genes trnK-UUU, rps16, trnG-UCC, atpF, rpoC1, trnL-UAA, trnV-UAC, petB, petD, rpl16, rpl2, ndhB, trnI-GAU, trnA-UGC, and ndhA contained one intron; genes clpP and ycf3 contained two introns. Phylogenetic results showed that A. alnifolia had the closest relationship with Sorbus folgneri (MK161058).
ABSTRACT
ABA has been widely acknowledged to regulate ethylene biosynthesis and signaling during fruit ripening, but the molecular mechanism underlying the interaction between these two hormones are largely unexplored. In the present study, exogenous ABA treatment obviously promoted fruit ripening as well as ethylene emission, whereas NDGA (Nordihydroguaiaretic acid, an inhibitor of ABA biosynthesis) application showed the opposite biological effects. Combined RNA-seq with time-course RT-PCR analysis, our study not only helped to illustrate how ABA regulated itself at the transcription level, but also revealed that ABA can facilitate ethylene production and response probably by regulating some crucial genes such as LeACS4, LeACO1, GR and LeETR6. In addition, investigation on the fruits treated with 1-MCP immediately after ABA exposure revealed that ethylene might be essential for the induction of ABA biosynthesis and signaling at the onset of fruit ripening. Furthermore, some specific transcription factors (TFs) known as regulators of ethylene synthesis and sensibility (e.g. MADS-RIN, TAGL1, CNR and NOR) were also observed to be ABA responsive, which implied that ABA influenced ethylene action possibly through the regulation of these TFs expression. Our comprehensive physiological and molecular-level analysis shed light on the mechanism of cross-talk between ABA and ethylene during the process of tomato fruit ripening.
