Plant Molecular Biology Reporter最新文献

Lateral branch angle (LBA) is an important agronomic trait that represents the plant’s growth habit in peanuts (Arachis hypogaea L.), and obtaining the ideotype is the goal of breeders. Although numerous studies have been conducted in the past few decades on both spreading (prostrate) and erect growth habits, the underlying mechanism governing the LBA remains elusive. In this study, bulked segregant analysis coupled with next-generation sequencing (BSA‐seq) was employed to map major quantitative trait loci (QTL) controlling LBA. Spreading (S) and erect (E) bulks from progenies of a recombinant inbred line (RIL) population (Xuhua 13 × F458) were sequenced. Through Δ(SNP‐index) analysis, we identified eight regions on chromosome B05 among 152,650,001–159,955,000 bp and one region on chromosome B09 corresponding to the genomic interval of 154,908,001 to 154,918,000 bp. The regions on chromosome B05 were further narrowed down using single nucleotide polymorphism (SNP) markers, and the gene associated with peanut LBA was mapped around the marker 15‐156 (156,921,591 bp) containing one annotated gene named Arahy.XAW92V, which may play a role in regulating cell growth. The results presented herein not only demonstrate the efficacy of BSA‐seq as a rapid strategy for mapping quantitative traits, such as LBA, but also provide compelling evidence supporting Arahy.XAW92V as a promising candidate gene associated with LBA in peanuts.

Inula britannica is a significant botanical species of plant in the Asteraceae family. The dried capitulum of this plant has been utilized as a traditional Chinese herbal remedy, exhibiting therapeutic properties in treating edema, alleviating nausea, and preventing vomiting. The formal designation for Inula britannica has been assigned to Pentanema britannicum. The whole chloroplast genome of I. britannica was constructed de novo in this study. The genomic characteristics were assessed and subsequently compared to those of five Inula species. I. britannica’s chloroplast genome had a length of 150,774 base pairs. The observed structure had a characteristic quadripartite arrangement, comprising a substantial single-copy section, a smaller single-copy region, and a pair of inverted repeat regions, measuring 82,451 bp, 18,423 bp, and 24,950 bp in length, respectively. The genome has been shown to have 109 distinct genes, comprising 79 protein-coding genes, four rRNA genes, and 26 tRNA genes. The chloroplast genome of I. britannica was found to have 49 lengthy repetitive sequences and 69 simple sequence repeats. The findings of the phylogenetic analysis revealed a significant correlation among I. britannica, I. janopinca, and I. linariifolia, followed by I. hupehensis. Our proposal suggests that “Inula britannica” is a more appropriate label for this particular species than “Pentanema britannicum.” Combining the K2p, ecorPrimers, and DNA polymorphic analysis results, eight regions can be distinguished from four Inula species after PCR and sangger sequencing. The reconstruction of ancestral character states revealed a series of changes from long spurs to alternative petal forms in the Inula species. The investigation of divergence time revealed that Inula underwent diversification during the late Pliocene period, specifically around 3.245 Mya. These findings will aid in establishing its evolutionary connections and taxonomy classification.

Genotyping by sequencing (GBS) is a very helpful approach and one of the most useful techniques for examining and analysing the genetic variation of various lines and varieties. GBS technology was used to identify single nucleotide polymorphisms (SNPs) and assess genetic variation in several watermelon accessions. GBS application in watermelon breeding programs has recently become a popular technique among many breeders. Watermelon (Citrullus lanatus L.) is a warm-season crop that is widely cultivated for its delicious fruit. And it is one of the most economically significant crops in the world. However, watermelon cultivation is frequently hampered by abiotic stressors such as drought and salinity. Recently, there has been a growing body of research on the mechanisms that allow watermelon to tolerate these stresses and improve crop yield. Generally, cucurbits are beneficial to human health, they provide necessary minerals, fibre, and nutrient components. Therefore, this review demonstrates the cutting edge of using GBS technology to identify genetic design of several features in watermelon to improve abiotic stresses (drought and saline). The application of the GBS technique has provided a distinct advantage in watermelon breeding studies. Based on GBS approach, many new candidate genes in watermelon lines control a variety of traits including saline and drought tolerance, fruit rind color, disease tolerance, nutrient components, size, and fruit shape were discovered. Modern breeding techniques are being used to develop economically viable vegetable crops that will meet customer preferences and needs. Further research is needed to enhance watermelon production.

Plant argonaute (AGO) proteins—chiefly AGO1 and 2—restrict viral infections. AGO1/2 also participate in developmental processes and are tightly regulated by microRNAs. Researchers have conducted extensive studies on the regulatory loop involving miR168/AGO1 in viral infections, though comparatively less attention has been given to the miR403/AGO2 system. Here, we simultaneously studied both regulatory systems in Arabidopsis plants infected with turnip mosaic virus (TuMV). TuMV simultaneously altered both miR168 and miR403 precursors as well as their mature forms at medium to late stages of infection. While TuMV decreased miRNA precursor molecules, it induced the overaccumulation of mature miRNA forms, without evidence of concomitant transcriptional alteration. The AGO1 protein remained at basal levels, whereas the AGO2 protein overaccumulated. The application of exogenous salicylic acid (SA) in healthy plants resulted in elevated AGO2 mRNA levels. Conversely, this hormone did not induce any significant changes in either AGO1 mRNA levels or those of miRs 168 and 403. This response is coherent with previous results, which showed enhanced levels of SA under TuMV infection and the partially differential sensitivity that AGO proteins have against this defense hormone. Our results also highlight the key role of AGO2 in leaves as an antiviral molecule and demonstrate the different responsiveness of the AGO1/miR168 and AGO2/miR403 systems regarding TuMV infection and SA response. Taken together, the results presented here are in line with previous reports studying abiotic and biotic impacts on microRNA biogenesis and AGO-dependent antiviral defense and further expand the knowledge of the miR403/AGO2 regulatory system.

Cytochrome P450 (CYP450) proteins are a large group of monooxygenase that play important roles in the biosynthesis of secondary metabolites and degradation of xenobiotics. However, the responses of CYP450 family to abiotic stresses have not been characterized in Brassica napus (B. napus). In this study, we identified a total of 384 CYP450 genes in Darmor-bzh, the rapeseed culture whose genome was wildly used as a reference for gene clone. The structure and localization analyses showed that BnaCYP450 genes have integrated heme-binding motif, contain 1–10 exons, unevenly distributed across all the 19 chromosomes, and mainly localized on chloroplast. Cis-regulation element analysis suggested that BnaCYP450 genes were transcriptionally regulated by hormone and multiple stress response signals. Transcript expression analyses identified 108, 85, 96, and 86 BnaCYP450s differentially expressed genes (DEGs) in response to salt stress, potassium deficiency, nitrogen stress, and cadmium toxicity, respectively. Gene ontology (GO) enrichment analysis indicated that these BnaCYP450 DEGs mainly enriched in molecular function of ion binding and oxidoreductase activity and the biological process of secondary product metabolism. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that they mainly involved in the pathway of isoflavonoid biosynthesis. Differential expression of BnaCYP450s to multiple abiotic stresses revealed the functional diversity of BnaCYP450 family in B. napus. This study gave a basic understanding of CYP450 genes in B. napus and provides multiple core BnaCYP450 genetic resources for improving plant resistance to multiple abiotic stresses.

Mulberry is a fast-growing perennial crop commercially exploited as the sole source of food for the mulberry silkworm, Bombyx mori, for the production of silk. Powdery mildew disease is a major foliar disease that greatly affects the sericulture industry. Understanding the genetic basis of powdery mildew disease resistance and its utilization for developing resistant varieties is the primary approach to mulberry crop improvement. Both natural and induced mutations impairing the function of the Mildew resistance Locus O (MLO) gene leading to powdery mildew resistance have been identified in different crop plants. However, more studies are required focusing on MLO gene-based resistance in natural germplasm. In this study, previously identified candidate genes, MLO2 and MLO6A, involved in powdery mildew susceptibility in mulberry were analyzed for gene expression, mutation, and alternative splice variants. In some tolerant accessions, MLO2 and MLO6A show either reduced or no elevated expression under infected conditions. Publicly available whole genome re-sequenced data analysis from mulberry accessions identified single amino acid substitutions in the MLO2 and MLO6A genes. Further, alternative splice variants of intron retention and exon skipping resulted in premature stop codon leading to the production of truncated MLO2 protein which were detected in tolerant mulberry accessions. This study will pave for better understanding of powdery mildew disease resistance and for breeding program.

Rice blast disease is one of the most disastrous diseases causing significant losses to the crop. In the humid weather conditions of north-eastern Himalayan region, the situation is highly devastating as the climate is very favorable to the fungus Magnaporthe oryzae. Development of resistant rice varieties is the most effective, economical, and environment-friendly way to control this disease. The study aimed to identify novel sources of resistant donor using agro-morphological and gene-based markers for their utilization in development of blast-resistant varieties with high yield potential. Phenotypic evaluation has classified the hundred landraces into resistant (13), moderately resistant (43), moderately susceptible (24), and susceptible (20). Fifty-nine genotypes were found to carry genes responsible for blast resistance, either singly or in combination. The genotype MN-62 was found to have a blast score of zero in field screening. The genetic frequencies of the major blast resistance genes ranged from 28 to 97%. The cluster analysis grouped the landraces into three major groups. Additionally, the association between blast genes was computed with blast score using a general linear model (GLM) and mixed linear model (MLM), revealing that the markers AP4007, AP56595, C1454, and RM208 were found to be associated with the trait. The landraces with six blast R-genes like Nungshang Phou, Ratkhara, Anandhi, RCPL 1–44, Ching Phou Khong Nombi, MN-31, Rona Yang, and RCPL-128 were also superior for agro-morphological traits. Similarly, the landraces MN-62, Tara Bali, Rato Bhan Joha, MN-47, RCPL 1–411, and CAU-R1 were promising regarding yield and blast resistance. The resistant lines with various combinations of blast resistance genes can be utilized for introgression of genes into the commercial varieties for durable resistance using marker-assisted backcrossing.

Salinity stress is one of the major abiotic stresses that significantly impacts plant growth and performance. Therefore, this study investigated the role of foliar-applied ascorbic acid (AsA) at a concentration of 2 mM as a mitigative approach to salt stress in barley during its vegetative stage. The research aimed to elucidate the genetic responses induced by AsA that potentially confer enhanced tolerance to salinity. A controlled environment experiment was conducted, wherein barley plants were subjected to salt stress and treated with a foliar application of AsA. Natural phenotypic variation showed an increment for all agronomical traits after the foliar application of AsA compared to saline environment (control). Highly significant markers were detected by using a genome-wide association study (GWAS) that are associated with all of the studied traits, underscoring the protective role of AsA under salt stress. Furthermore, the study identified several novel stress-responsive genes influenced by AsA treatment, pointing to complex genetic networks underlying salt stress mitigation. For instance, the gene HORVU.MOREX.r3.2HG0199440 at position (622,219,977–622,220,459 bp) on 2H, which is annotated as V-type ATP synthase beta chain, helps to maintain cellular redox balance during stress conditions. This research paves the way for future work on the practical applications of AsA in agriculture, especially in breeding programs aimed at enhancing salt stress tolerance in barley and similar cereals.

Abstract

Environmental stresses are responsible for limiting soybean yield. To mitigate the impacts generated by water deficit, molecular biology tools are being used to develop genetically modified plants. Previous studies showed that two independent events (B1 and B3) of soybean transgenic plants expressing a Solanum nigrum osmotin (SnOLP) had an increment in drought tolerance. The present study aims to investigate the modulated pathways that results in the drought tolerance promoted by osmotin overexpression in soybean. Transgenic and non-transgenic (NT) plants in the vegetative stage were submitted to water deficit by irrigation suppression for seven days. Control plants were kept irrigated. Physiological variables were monitored and confirmed that the transgenic plants present better performance when compared to the NT plants. The total RNA extracted from leaves was sequenced and data was normalized by DESeq2. A total of 2044 and 1505 differentially expressed genes (DEGs) were identified in B1 and B3 events, respectively. Regarding the B1 event, 769 genes were upregulated and 1275 downregulated. For B3, 541 genes were upregulated and 964 genes were downregulated. Excluding common differentially expressed genes (DEGs) between transgenic and non-transgenic (NT) plants yielded 395 upregulated and 234 downregulated genes, which were shared by B1 and B3 events. The metabolic pathways and gene ontology categories identified are known to be involved in plant responses to drought. Hormonal, photosynthetic, carbohydrate and amino acid metabolism, reactive oxygen species, and post-translational modifications pathways were significantly modulated in transgenic plants. Altogether, the results suggest that osmotin promotes tolerance through an increment in the plant responses elicited by drought.

Bacterial leaf blight (BLB) disease is one of the most important diseases of rice in India and worldwide. The management of this disease becomes extremely challenging due to the presence of Xoo races with varying level of virulence and diversity. The development of BLB-resistant rice lines with the help of marker-assisted selection has been proven as one of the most effective strategies to sustain rice cultivation. This study demonstrates marker-assisted introgression and pyramiding of two broad-spectrum BLB genes (Xa33 and Xa38) into the background of “CO43,” a popular fine white-grained rice cultivar, tolerant to saline coastal areas in southern India. Two separate marker-assisted backcrossing schemes were used, and at each stage of backcrossing, foreground, recombinant, and background selection were carried out. Backcross-derived lines possessing either Xa33 or Xa38 along with maximum genome recovery of “CO43” were identified at BC₂F₁ generation, intercrossed with each other to pyramid the genes, and selfed to identify homozygous lines for the pyramided genes. The performance of the improved “CO43” lines, such as lines # 2_7_78, 2_7_102, 6_9_65, and 6–8-76 exhibited enhanced broad-spectrum resistance to BLB (lesion length, LL 0.0 ± 0.0 to 0.9 ± 0.1 cm). Furthermore, the improved “CO43” lines maintained the agro-morphological features of the recurrent parent along with enhanced BLB resistance. These lines with effective and durable resistance would contribute to sustainable rice production in coastal areas of southern India.