Identification and expression analysis of the Xyloglucan transglycosylase/hydrolase (XTH) gene family under abiotic stress in oilseed (Brassica napus L.).

XTH genes are key genes that regulate the hydrolysis and recombination of XG components and plays role in the structure and composition of plant cell walls. Therefore, clarifying the changes that occur in XTHs during plant defense against abiotic stresses is informative for the study of the plant stress regulatory mechanism mediated by plant cell wall signals. XTH proteins in Arabidopsis thaliana was selected as the seed sequences in combination with its protein structural domains, 80 members of the BnXTH gene family were jointly identified from the whole genome of the Brassica napus ZS11, and analyzed for their encoded protein physicochemical properties, phylogenetic relationships, covariance relationships, and interoperating miRNAs. Based on the transcriptome data, the expression patterns of BnXTHs were analyzed in response to different abiotic stress treatments. The relative expression levels of some BnXTH genes under Al, alkali, salt, and drought treatments after 0, 6, 12 and 24 h were analyzed by using qRT-PCR to explore their roles in abiotic stress tolerance in B. napus. BnXTHs showed different expression patterns in response to different abiotic stress signals, indicating that the response mechanisms of oilseed rape against different abiotic stresses are also different. This paper provides a theoretical basis for clarifying the function and molecular genetic mechanism of the BnXTH gene family in abiotic stress tolerance in rapeseed.

Identification and Expression Analysis of the Isopentenyl Transferase (IPT) Gene Family under Lack of Nitrogen Stress in Oilseed (Brassica napus L.).

BnIPT gene family members in Brassica napus and analyzing their expression under different exogenous hormones and abiotic stress treatments to provide a theoretical basis for clarifying their functions and molecular genetic mechanisms in nitrogen deficiency stress tolerance of B. napus. Using the Arabidopsis IPT protein as the seed sequence, combined with the IPT protein domain PF01715, 26 members of the BnIPT gene family were identified from the whole genome of the rape variety ZS11. Additionally, the physicochemical properties and structures, phylogenetic relationships, synteny relationships, protein-protein interaction network, and gene ontology enrichment were analyzed. Based on transcriptome data, the expression patterns of the BnIPT gene under different exogenous hormone and abiotic stress treatments were analyzed. We used the qPCR method to identify the relative expression level of BnIPT genes that may be related to the stress resistance of rapeseed in transcriptome analysis under normal nitrogen (N: 6 mmol·L-1) and nitrogen deficiency (N: 0) conditions and analyzed its effect on rapeseed under nitrogen deficiency stress role in tolerance. In response to nitrogen deficiency signals, the BnIPT gene showed a trend of up-regulation in shoots and down-regulation in roots, indicating that it may affect the process of nitrogen transport and redistribution to enhance the stress resistance of rapeseed to respond to the nitrogen deficiency stress. This study provides a theoretical basis for clarifying the function and molecular genetic mechanism of the BnIPT gene family in nitrogen deficiency stress tolerance in rape.

miRNAs and lncRNAs in tomato: Roles in biotic and abiotic stress responses.

Plants are continuously exposed to various biotic and abiotic stresses in the natural environment. To cope with these stresses, they have evolved a multitude of defenses mechanisms. With the rapid development of genome sequencing technologies, a large number of non-coding RNA (ncRNAs) have been identified in tomato, like microRNAs (miRNAs) and long non-coding RNAs (lncRNAs). Recently, more and more evidence indicates that many ncRNAs are involved in plant response to biotic and abiotic stresses in tomato. In this review, we summarize recent updates on the regulatory roles of ncRNAs in tomato abiotic/biotic responses, including abiotic (high temperature, drought, cold, salinization, etc.) and biotic (bacteria, fungi, viruses, insects, etc.) stresses. Understanding the molecular mechanisms mediated by ncRNAs in response to these stresses will help us to clarify the future directions for ncRNA research and resistance breeding in tomato.

The karyotype, genome survey, and assembly of Mud artemisia (Artemisia selengensis).

BACKGROUND: Artemisia selengensis is traditional Chinese medicine and phytochemical analysis indicated that A. selengensis contains essential oils, fatty acids and phenolic acids. The lack of reference genomic information may lead to tardiness in molecular biology research of A. selengensis. METHOD AND RESULTS: Karyotype analysis, genome survey, and genome assembly was employed to acquire information on the genome structure of A. selengensis. The chromosome number is 2n = 2x = 36, karyotype formula is 28 m + 8Sm, karyotype asymmetry coefficient is 58.8%, and karyotypes were symmetric to Stebbins' type 2A. Besides, the flow cytometry findings reported that the mean peak value of fluorescent intensity is 1,170,677, 2C DNA content is 12 pg and the genome size was estimated to be approximately 5.87 Gb. Furthermore, the genome survey generates 341,478,078 clean reads, unfortunately, after K-mer analysis, no significant peak can be observed, the heterozygosity, repetitive rate and genome size was unable to estimated. It is speculated that this phenomenon might be due to the complexity of genome structure. 37,266 contigs are preliminary assembled with Oxford Nanopore Technology (ONT) sequencing, totaling 804 Mb and GC content was 34.08%. The total length is 804,475,881 bp, N50 is 29,624 bp, and the largest contig length is 239,792 bp. CONCLUSION: This study reveals the preliminary information of genome size of A. selengensis. These findings may provide supportive information for sequencing and assembly of whole-genome sequencing and encourage the progress of functional gene discovery, genetic improvement, evolutionary study, and structural studies of A. selengensis.