Plant Molecular Biology Reporter最新文献

The most detrimental disease of finger millet (Eleusine coracana) is blast caused by Pyricularia grisea inflicting substantial yield losses. This study evaluated 100 finger millet genotypes from a core collection for disease response to leaf, neck and finger blast. Good phenotypic variability in the genotypes was recorded for blast reactions. None of the accessions was resistant to leaf blast; however, 12 and 27 accessions were resistant to neck and finger blast, respectively. A total of 28 accessions showed resistance to both neck and finger blast. A significant positive correlation was observed between neck and finger blast. Genotyping of 50 accessions differing in disease reactions to neck blast was performed using 30 SSR markers 17 of which proved to be polymorphic. A total of 51 alleles were detected with the mean value of 2.55 alleles per locus. The PIC values of the polymorphic SSR markers ranged from 0.03 to 0.98, and the dendrogram grouped these genotypes in 13 clusters. Cluster I and II comprised of resistant accessions, whereas cluster VIII formed the susceptible group. SSR markers UGEP 76 and UGEP 102 consistently produced bands in neck blast susceptible and highly susceptible germplasms, indicating their probable association with neck blast susceptibility gene(s). Our results showed that the core collection has appreciable diversity for blast reactions both phenotypically and genotypically.

To investigate the genetic diversity of 40 melon and cantaloupe cultivars, which were collected from the central regions of Iran and southwestern Afghanistan, inter-simple sequence repeat (ISSR) primers and several morphological traits were used. The results demonstrate that 12 selected ISSR markers generated polymorphic bands with a distinct band pattern. There were a total of 150 bands created, with 95 bands exhibiting polymorphism (62.44% diversity). Based on shape and characteristics, cluster analysis and principal coordinate analysis (PCoA) classified the cultivars into five groups: winter and late ripening, medium ripening, sweet, and early melons, including cantaloupe and melon. In the majority of instances, PCoA was consistent with cluster analysis, whereas the molecular data did not perfectly match the morphological results. The results of the analysis classified the morphological characteristics of individuals into five groups: the first group comprised nine Iranian and Afghan melon genotypes with long, thin-skinned forms and intermediate medium ripening, and the second group comprised five Afghan melon genotypes with late ripening, winter ripe, and thick skin and flesh. The third group of 11 Iranian and Afghan melon cultivars was typically medium-sized, elliptical-shaped melons with thin skin. The fourth group consists of two Iranian melons with small seeds, small fruit, rapid maturation, and no flavor. The final group possessed dense and tender flesh, a spherical shape, and large seeds. In conclusion, morphological traits and ISSR analysis could be useful tools for classifying melon germplasm for future breeding applications. The morphological and molecular similarities between Afghan and Iranian cultivars suggest their origin.

Phosphate is one of the major elements that significantly affects fruit yield and quality. The aim of the study was to determine whether using phosphorus-solubilizing bacteria could produce high-quality apple nursery trees. Five different treatments were tested on a “Granny Smith” apple cultivar that was grafted onto an M.9 rootstock. These were 100% P, 50% P, 50% P + Bacillus megatarum (plant growth promoting rhizobacteria, PGPR), 0%P, and 0%P + PGPR. The study also identified the SPX gene family, which is essential for plant growth and development and responds to phosphorus (P) stress. A total of 72 SPX genes were identified in different plant species based on structural and phylogenetic analysis. The apple genome contains seven different SPX genes distributed on five of the 17 chromosomes. Gene structure and motif analysis showed that SPX genes show a relatively conserved exon/intron arrangement and motif composition in five different species: apple, strawberry, peach, apricot, and grape. Protein–protein network analysis showed that SPX proteins are closely related to proteins involved in P metabolism in apple. The digital expression profiles of MdSPX genes among 47 apple tissues were characterized to provide insight into their potential functions. RT-qPCR revealed that the expression level of all MdSPXs was significantly downregulated in 50% P + PGPR treatments, indicating that 50% P combined with PGPR is effectively taken up by the plant, saving it from Pi starvation. These results not only confirm the key role of MdSPXs in Pi homeostasis and the Pi signaling pathway but also clarify the importance of Pi-solubilizing bacteria in plant nutrition.

Abstract

Nitrogen plays a crucial role in plant metabolism, growth, and development of plants, and its deficiency leads to severe growth retardation and reduced grain yield. The efficient utilization of nitrogenous fertilizers is needed to enhance crop yield and also to fetch the food demand of the world population. The accumulated nitrogen in the ecosystem leads to severe environmental pollution and health hazards to inhabited animals. However, nitrogen inside plants is regulated by a set of nitrogen metabolism genes, promoters, and transcription factors. Further, the identification and characterization of nitrogen metabolism genes in crop plants is a prerequisite for developing tailored crop plants for increased nitrogen use efficiency (NUE), grain yield, biomass, and other economic traits. Moreover, NUE is a complex trait, and breeding crops for improving NUE is still in the infancy stage. Therefore, a targeted and holistic approach is required for enhanced nitrogen uptake and its utilization. The precise modulation of key genes of nitrogen metabolism, amino acid biosynthesis, and carbon metabolism could result in enhancement of NUE, and the engineered crop plants for NUE traits were reported to be superior in terms of NUE and also incurred higher grain yield, biomass, and improved agronomical parameters as that of cultivated crop cultivars. In this review, we described the basics of nitrogen metabolism, genomics, and recently targeted genetic engineering strategies employed in crop plants for improving NUE.

The global challenge of crop loss due to salt stress became increasingly significant, especially in the context of meeting the rising demands of a growing world population. This review focuses on the impact of salt stress on leguminous plants throughout their entire growth stages. Additionally, it provides a comprehensive overview of the molecular strategies employed to enhance the performance of legumes in saline environments. In addressing this issue, the review critically assesses recent advancements in bolstering legume salt stress tolerance through genetic engineering. This approach is acknowledged for its efficiency compared to traditional breeding methods, facilitating the transfer of desired genes without introducing extraneous genetic material from the donor organism. The review also examines the critical role of preventing ionic toxicity in transgenic leguminous plants by expressing foreign Na⁺/H⁺ antiporter genes and transcription factors. Furthermore, the review emphasizes the positive outcomes observed when introducing or overexpressing genes related to compatible solutes in transgenic legumes. These genetic modifications have proven effective in enhancing the tolerance of legumes to salinity-induced osmotic stress. Another aspect explored in the review is the improving of salt stress-induced oxidative stress management in various transgenic legume species. This is achieved through the expression of both enzymatic and non-enzymatic genes. Finally, the review explores the manipulation of candidate genes to improve nodule performance under salt stress. By identifying and modifying specific genes, researchers can pave the way for leguminous plants to thrive in salt-affected environments.

Germin-like proteins (GLPs) play crucial roles in disease resistance, stress tolerance, and plant defense responses in various crop species. This review explores the intricate role of GLP gene expression and its modulation by cis-acting regulatory elements (CAREs) under biotic and abiotic stress in major crops. In rice, OsGLP2-1 and OsGLP3-7 have been identified as positive regulators of disease resistance. Similarly, TaGLP genes in wheat and VvGLP3 in grapes have been associated with powdery mildew resistance. Additionally, ZmGLP1 in maize and StGLP5 in potato contribute to defense against Bipolaris maydis and salt stress, respectively. AhGLPs in peanuts respond to drought stress, while GmGLP10 in soybean demonstrates a response to Sclerotinia sclerotiorum infection. Research in cotton has unveiled GhABP19 and GhGLP2 as GLPs involved in plant defense responses to wilt disease. Analysis of GLP gene promoters has revealed the presence of stress-responsive CAREs that modulate gene expression under biotic and abiotic stresses. Transgenic overexpression of GLP genes in different plant species, such as potato, tobacco, and Arabidopsis, has resulted in enhanced resistance to fungal pathogens, oxidative stress, and abiotic stresses. CRISPR/Cas9 genome editing has provided insights into UV-B stress response mechanisms. Promising outcomes from transgenic studies and CRISPR genome editing present exciting opportunities to improve disease resistance and stress tolerance in crops. These findings significantly enhance our understanding of the critical roles played by GLPs in crop resilience, paving the way for the development of stress-resistant crops to ensure sustainable global food security.

To better understand the relationship between MdMCs and ethylene during apple fruit ripening. “Golden Delicious” apple fruit were treated with ethephon (0.2 mmol L⁻¹) and ethylene action inhibitor 1-methylcyclopropene (1-MCP) (1 µL L⁻¹) after harvest, and the ethylene-responsive transcription factor MdERF2 was transiently over-expressed in apple fruit at commercial maturity. Our results showed that climacteric peaks of respiration rate and ethylene production were advanced by ethephon treatment while delayed by application of 1-MCP. Ethephon treatment increased activity of MC, content of malondialdehyde (MDA), and relative electrical conductivity (REC) compared with controls during ripening, while 1-MCP treatment had the opposite effects. Expression of MdMC04, MdMC07, MdMC12, MdMC14, MdMC16, MdMC18, MdMC19, and MdMC20 was differentially induced by ethephon treatment, while their expression was generally downregulated by application of 1-MCP compared with controls during ripening. MdMC06 expression was induced at the late ripening stage by 1-MCP treatment but reduced by ethephon application during ripening compared to the control group. Transcript levels of MdMC01 and MdMC13 were promoted by both 1-MCP and ethephon treatments during ripening. In contrast, expression of MdMC17, MdMC05, MdMC02, MdMC21, MdMC10, and MdMC09 was differentially reduced after application of ethephon and 1-MCP during ripening compared with controls. Expression patterns of MdMCs varied in fruit transiently over-expressing MdERF2 during ripening. These results indicated that MdMCs expression was modulated by ethylene signal during apple ripening. Our findings would be useful for further unraveling the molecular mechanism of ethylene signaling in modulating MC genes during apple ripening.

Hemsleya zhejiangensis C.Z. Zhang (Cucurbitaceae) is a rare and endangered plant species endemic to eastern China and is listed as a key protected species in Zhejiang Province. However, owing to the lack of genomic information and efficient molecular markers, the genetic diversity and population structure of this species remain unknown. In this study, we conducted transcriptome sequencing and de novo assembly of two H. zhejiangensis individuals to develop expressed sequence tag-simple sequence repeat (EST-SSR) markers. Using CandiSSR software, 345 candidate polymorphic EST-SSRs were identified. Twenty EST-SSRs were developed for illustrating the genetic diversity and structure of the four populations of H. zhejiangensis. The populations of ZX (Taishun, Zhejiang) and WYL (Taishun, Zhejiang) have the closest kinship, whereas the populations from WYS (Mount Wuyi, Fujian) showed the farthest kinship with all populations from Zhejiang, suggesting that geographic isolation may significantly impede gene exchange and reduce the genetic diversity of this species. The availability of genomic resource will facilitate subsequent population genetic analyses and molecular breeding, which will be of great significance in formulating strategies for the conservation and utilization of H. zhejiangensis.

Abstract

Quantitative trait locus (QTL) mapping and genetic map are of great significance for ornamental sunflowers in China. In this study, a total of 956.50 Mbp data were obtained, the average Q30 was 93.76%, the average GC content was 42.43%, and the GC distribution of the parents and F₂ population of the ornamental sunflowers was normal. At the same time, the double-end comparison efficiency of control data was 90.28%, and the enzyme digestion efficiency was 92.01%. The Specific-Locus Amplified Fragment (SLAF) library construction was normal. Furthermore, a total of 734,893 SLAF markers were obtained, among which 127,855 were polymorphic SLAF markers and 38,908 could be used for genetic map construction, and the effective polymorphism of the parents was 5.29%. Moreover, we constructed a total of 17 linkage groups, with 6181 markers in the QTL mapping, the total map distance was 2608.66 cM, the marker integrity in the figure above was 99%, the proportion of double exchange was 0.05, the sequencing depth of the parents was 42.455 × , and the progeny was 9.24 × . The relationship of traits (plant height, stem diameter, disk diameter, number of petals, leaf number, stigma color, petal color, petiole color) and QTL mapping was closely related to show the best of ornamental effect.

C151 is a PVY-resistant flue-cured tobacco line, but the resistance mechanism is not clear. According to previous research results, the Va gene (Ntab0942120) in tobacco determines tobacco susceptibility to PVY, and Va deletion in the tobacco line VAM results in PVY resistance. To explore the correlation between the resistance mechanism of C151 and the Va gene, genomic-level detection of the Va gene was performed, and the results showed that there was no Va gene in C151. Pathological test results showed obvious susceptible symptoms in the C151 transformants with Va overexpression, which indicated that the resistance mechanism of C151 was caused by the loss of the Va gene. By examining molecular markers on chromosome 21, in which the Va gene is located, deletion of three markers adjacent to the Va gene occurred in C151, indicating that the PVY resistance of C151 also originates from a large deletion on chromosome 21; however, the mechanism behind this deletion remains unclear.