Functional Differences of Grapevine Circular RNA Vv-circPTCD1 in Arabidopsis and Grapevine Callus under Abiotic Stress.

Circular RNAs (circRNAs) serve as covalently closed single-stranded RNAs and have been proposed to influence plant development and stress resistance. Grapevine is one of the most economically valuable fruit crops cultivated worldwide and is threatened by various abiotic stresses. Herein, we reported that a circRNA (Vv-circPTCD1) processed from the second exon of the pentatricopeptide repeat family gene PTCD1 was preferentially expressed in leaves and responded to salt and drought but not heat stress in grapevine. Additionally, the second exon sequence of PTCD1 was highly conserved, but the biogenesis of Vv-circPTCD1 is species-dependent in plants. It was further found that the overexpressed Vv-circPTCD1 can slightly decrease the abundance of the cognate host gene, and the neighboring genes are barely affected in the grapevine callus. Furthermore, we also successfully overexpressed the Vv-circPTCD1 and found that the Vv-circPTCD1 deteriorated the growth during heat, salt, and drought stresses in Arabidopsis. However, the biological effects on grapevine callus were not always consistent with those of Arabidopsis. Interestingly, we found that the transgenic plants of linear counterpart sequence also conferred the same phenotypes as those of circRNA during the three stress conditions, no matter what species it is. Those results imply that although the sequences are conserved, the biogenesis and functions of Vv-circPTCD1 are species-dependent. Our results indicate that the plant circRNA function investigation should be conducted in homologous species, which supports a valuable reference for further plant circRNA studies.

Effects of exogenous plant regulators on growth and development of "Kyoho" grape under salt alkali stress.

Salinity is one of the major abiotic stresses besides drought and cold stress. The application of plant growth regulators (PGRs) is an effective method to mitigate yield losses caused by salinity. However, we investigated the effects of exogenous regulatory substances (γ-aminobutyric acid (GABA), salicylic acid (SA), and brassinolide (BR) on the growth and development of "Kyoho" grapevine under salt stress. The results showed that exogenous regulators GABA, SA, and BR alleviated the inhibition of grape growth by saline stress and regulated the effects of salinity stress on grape fruit development and quality. All three regulators significantly increased fruit set, cross-sectional diameter, weight per unit, and anthocyanin content. In conclusion, this study provides a theoretical basis for grape production practices by using exogenous aminobutyric acid (GABA), salicylic acid (SA), and brassinolide (BR) to mitigate the hazards of salinity stress.

Root-Zone Restriction Regulates Soil Factors and Bacterial Community Assembly of Grapevine.

Root-zone restriction induces physiological stress on roots, thus limiting the vegetative and enhancing reproductive development, which promotes fruit quality and growth. Numerous bacterial-related growth-promoting, stress-mitigating, and disease-prevention activities have been described, but none in root-restricted cultivation. The study aimed to understand the activities of grapevine bacterial communities and plant-bacterial relationships to improve fruit quality. We used High-throughput sequencing, edaphic soil factors, and network analysis to explore the impact of restricted cultivation on the diversity, composition and network structure of bacterial communities of rhizosphere soil, roots, leaves, flowers and berries. The bacterial richness, diversity, and networking were indeed regulated by root-zone restriction at all phenological stages, with a peak at the veraison stage, yielding superior fruit quality compared to control plants. Moreover, it also handled the nutrient availability in treated plants, such as available nitrogen (AN) was 3.5, 5.7 and 0.9 folds scarcer at full bloom, veraison and maturity stages, respectively, compared to control plants. Biochemical indicators of the berry have proved that high-quality berry is yielded in association with the bacteria. Cyanobacteria were most abundant in the phyllosphere, Proteobacteria in the rhizosphere, and Firmicutes and Bacteroidetes in the endosphere. These bacterial phyla were most correlated and influenced by different soil factors in control and treated plants. Our findings are a comprehensive approach to the implications of root-zone restriction on the bacterial microbiota, which will assist in directing a more focused procedure to uncover the precise mechanism, which is still undiscovered.

Coding of Non-coding RNA: Insights Into the Regulatory Functions of Pri-MicroRNA-Encoded Peptides in Plants.

Peptides composed of a short chain of amino acids can play significant roles in plant growth, development, and stress responses. Most of these functional peptides are derived by either processing precursor proteins or direct translation of small open reading frames present in the genome and sometimes located in the untranslated region sequence of a messenger RNA. Generally, canonical peptides serve as local signal molecules mediating short- or long-distance intercellular communication. Also, they are commonly used as ligands perceived by an associated receptor, triggering cellular signaling transduction. In recent years, increasing pieces of evidence from studies in both plants and animals have revealed that peptides are also encoded by RNAs currently defined as non-coding RNAs (ncRNAs), including long ncRNAs, circular RNAs, and primary microRNAs. Primary microRNAs (miRNAs) have been reported to encode regulatory peptides in Arabidopsis, grapevine, soybean, and Medicago, called miRNA-encoded peptides (miPEPs). Remarkably, overexpression or exogenous applications of miPEPs specifically increase the expression level of their corresponding miRNAs by enhancing the transcription of the MIRNA (MIR) genes. Here, we first outline the current knowledge regarding the coding of putative ncRNAs. Notably, we review in detail the limited studies available regarding the translation of miPEPs and their relevant regulatory mechanisms. Furthermore, we discuss the potential cellular and molecular mechanisms in which miPEPs might be involved in plants and raise problems that needed to be solved.

The complete chloroplast genome sequence of Vitis vinifera × Vitis labrusca 'Shenhua'.

Vitis vinifera × Vitis labrusca 'Shenhua' is a tetraploid grape, a Franco-american species. This study first published the complete chloroplast genome of Vitis vinifera × Vitis labrusca 'Shenhua' was assembled. The chloroplast genome is 160928 bp in length, including a large single copy region (89,148 bp), a small single-copy region (19,072 bp) and a pair of inverted repeats of 26,354 bp. The chloroplast genome encodes 133 genes, comprising 88 CDSs, 37 tRNA genes and 8 rRNA genes. The phylogenetic tree demonstrated that Vitis vinifera × Vitis labrusca 'Shenhua' is different from the other 16 varieties.

The complete chloroplast genome sequence of Vitis amurensis 'Shuanghong'.

Vitis amurensis 'Shuanghong' is a hybrid offspring of wild grapes. This study first releases the complete chloroplast genome of V. amurensis 'Shuanghong' and subjected the sample to phlogenetic analysis. The chloroplast genome is 161,558 bp in length, and comprises a small single-copy region (19,336 bp) and a large single-copy region (89,744 bp), which are seperated by a pair of inverted repeat regions. The chloroplast genome encodes 133 genes, including 88 CDSs, 8 rRNA genes, and 37 tRNA genes. The phylogenetic tree showed that V. amurensis 'Shuanghong' is most closely related to Vitis vinifera.

The complete chloroplast genome sequence of Vitis vinifera Muscat Hamburg.

Vitis vinifera Muscat Hamburg is Eurasian species, which is widely cultivated all over the world. In this study, the complete chloroplast genome of V. vinifera Muscat Hamburg is assembled for the first time. The chloroplast genome is 160,915 bp in length, and comprises a 19,072 bp small single copy region and an 89,135 bp large single copy region, which are seperated by a pair of inverted repeat regions. The chloroplast genome contains 133 genes, including 88 CDSs, 8 rRNA genes and 37 tRNA genes. The phylogenetic tree analysis showed that V. vinifera Muscat Hamburg was the closest to V. vinifera.