[学术文献] Genome-Wide Identification and Homoeologous Expression Analysis of PP2C Genes in Wheat (Triticum aestivum L.) 进入全文
Plant protein phosphatase 2Cs (PP2Cs) play crucial roles in phytohormone signaling, developmental processes, and both biotic and abiotic stress responses. However, little research has been conducted on the PP2C gene family in hexaploid wheat (Triticum aestivum L.), which is an important cereal crop. In this study, a genome-wide investigation of TaPP2C gene family was performed. A total of 257 homoeologs of 95 TaPP2C genes were identified, of which 80% of genes had all the three homoeologs across A, B, and D subgenomes. Domain analysis indicated that all the TaPP2C homoeologs harbored the type 2C phosphatase domains. Based on the phylogenetic analysis, TaPP2Cs were divided into 13 groups (A-M) and 4 single branches, which corresponded to the results of gene structure and protein motif analyses. Results of chromosomal location and synteny relationship analysis of TaPP2C homoeologs revealed that known chromosome translocation events and pericentromeric inversions were responsible for the formation of TaPP2C gene family. Expression patterns of TaPP2C homoeologs in various tissues and under diverse stress conditions were analyzed using publicly available RNA-seq data. The results suggested that TaPP2C genes regulate wheat developmental processes and stress responses. Homoeologous expression patterns of TaPP2C triad homoeologs from A, B, and D subgenomes, revealed expression bias within triads under the normal condition, and variability in expression under different stress treatments. Quantitative real-time PCR (qRT-PCR) analysis of eight TaPP2C genes in group A revealed that they were all up-regulated after abscisic acid treatment. Some genes in group A also responded to other phytohormones such as methyl jasmonate and gibberellin. Yeast two-hybrid assays showed that group A TaPP2Cs also interacted with TaSnRK2.1 and TaSnRK2.2 from subclass II, besides with subclass III TaSnRK2s. TaPP2C135 in group A was transformed into Arabidopsis and germination assay revealed that ectopic expression of TaPP2C135 in Arabidopsis enhanced its tolerance to ABA. Overall, these results enhance our understanding of the function of TaPP2Cs in wheat, and provide novel insights into the roles of group A TaPP2Cs. This information will be useful for in-depth functional analysis of TaPP2Cs in future studies and for wheat breeding.
[学术文献] Identification and Characterization of Wheat Yellow Striate Virus, a Novel Leafhopper-Transmitted Nucleorhabdovirus Infecting Wheat 进入全文
A new wheat viral disease was found in China. Bullet-shaped viral particles within the nucleus of the infected wheat leave cells, which possessed 180–210 nm length and 35–40 nm width, were observed under transmission electron microscopy. A putative wheat-infecting rhabdovirus vectored by the leafhopper Psammotettix alienus was identified and tentatively named wheat yellow striate virus (WYSV). The full-length nucleotide sequence of WYSV was determined using transcriptome sequencing and RACE analysis of both wheat samples and leafhoppers P. alienus. The negative-sense RNA genome of WYSV contains 14,486 nucleotides (nt) and seven open reading frames (ORFs) encode deduced proteins in the order N-P-P3-M-P6-G-L on the antisense strand. In addition, WYSV genome has a 76-nt 3′ leader RNA and a 258-nt 5′ trailer, and the ORFs are separated by conserved intergenic sequences. The entire genome sequence shares 58.1 and 57.7% nucleotide sequence identity with two strains of rice yellow stunt virus (RYSV-A and RYSV-B) genomes, respectively. The highest amino acid sequence identity was 63.8% between the L proteins of the WYSV and RYSV-B, but the lowest was 29.5% between the P6 proteins of these viruses. Phylogenetic analysis firmly established WYSV as a new member of the genus Nucleorhabdovirus. Collectively, this study provided evidence that WYSV is likely the first nucleorhabdovirus described infecting wheat via leafhopper P. alienus transmission.
[学术文献] Genetic Diversity and Population Structure of F3:6 Nebraska Winter Wheat Genotypes Using Genotyping-By-Sequencing 进入全文
The availability of information on the genetic diversity and population structure in wheat (Triticum aestivum L.) breeding lines will help wheat breeders to better use their genetic resources and manage genetic variation in their breeding program. The recent advances in sequencing technology provide the opportunity to identify tens or hundreds of thousands of single nucleotide polymorphism (SNPs) in large genome species (e.g., wheat). These SNPs can be utilized for understanding genetic diversity and performing genome wide association studies (GWAS) for complex traits. In this study, the genetic diversity and population structure were investigated in a set of 230 genotypes (F3:6) derived from various crosses as a prerequisite for GWAS and genomic selection. Genotyping-by-sequencing provided 25,566 high-quality SNPs. The polymorphism information content (PIC) across chromosomes ranged from 0.09 to 0.37 with an average of 0.23. The distribution of SNPs markers on the 21 chromosomes ranged from 319 on chromosome 3D to 2,370 on chromosome 3B. The analysis of population structure revealed three subpopulations (G1, G2, and G3). Analysis of molecular variance identified 8% variance among and 92% within subpopulations. Of the three subpopulations, G2 had the highest level of genetic diversity based on three genetic diversity indices: Shannon’s information index (I) = 0.494, diversity index (h) = 0.328 and unbiased diversity index (uh) = 0.331, while G3 had lowest level of genetic diversity (I = 0.348, h = 0.226 and uh = 0.236). This high genetic diversity identified among the subpopulations can be used to develop new wheat cultivars.
[前沿资讯] Genotypic Variation in the Root and Shoot Metabolite Profiles of Wheat (Triticum aestivum L.) Indicate Sustained, Preferential Carbon Allocation as a Potential Mechanism in Phosphorus Efficiency 进入全文
植物代谢产物对营养缺乏反应水平的变化可以反映植物如何利用稀缺资源。本项目研究了不同磷利用效率(PUE)下小麦根、芽代谢产物基因型的变化。在低磷和播种后的28天(DAS)，小麦育种系RAC875 (P有效率)比小麦品种多产生42%的芽生物量，而Wyalkatchem (P低效)。在低磷胁迫下，叶片和根系的代谢产物谱发生了明显的变化，且存在显著的基因型变异。在低磷条件下，两种小麦基因型的根中棉子糖和1-蔗果三糖均有明显的增加，RAC875的积累量高于Wyalkatchem；植株叶片中棉子糖和1-蔗果三糖含量无显著增加。低磷对两种基因型的蔗糖、麦芽糖、葡萄糖和果糖水平均无显著影响，而RAC875中磷酸化糖(葡萄糖-6-P和果糖-6-P)保持不变，而在Wyalkatchem中，葡萄糖-6-P在根中显著降低，果糖-6-P在叶和根中含量显著降低。在低磷胁迫下，两种小麦基因型的根中甘油-3-P含量均降低了2倍。在根中，RAC875的富马酸盐、苹果酸盐、马来酸盐和依他酸盐含量明显低于Wyalkatchem，而在RAC875中，低磷增强了有机酸的渗出，而在Wyalkatchem中则没有。RAC875显示更高的天冬氨酸积累,谷氨酰胺和β-丙氨酸叶子比Wyalkatchem在低P供应。更高棉子糖的积累；1-蔗果三糖在根部的积累；天冬氨酸、谷氨酸盐和β-丙氨酸在叶子中的积累似乎与RAC875增强有关。葡萄糖-6-P和果糖-6-P对糖酵解具有重要作用，维持这些代谢产物可以使RAC875在缺磷条件下维持碳水化合物代谢和地上植株生物量。本项研究表明在PUE和关键代谢途径下，不同的小麦品种之间可以观察到代谢物谱的差异，并在有效的基因型中维持代谢途径的差异，以确保在低磷条件下的碳供应。