Plant Molecular Biology Reporter最新文献

Drought stress is a major limiting factor for rice production globally. The current climatic changes have further increased the incidence and duration of droughts worldwide. On the other hand, seaweed extracts have been extensively studied as biostimulants that improve plant growth, nutrition, quality, yield, and stress tolerance of rice (Oryza sativa). Different types of seaweeds have been employed for biostimulant preparation, of which algae is most commonly used. Of particular interest were Galaxaura oblongata and Turbenaria ornate seaweeds, as biostimulants that inoculate with soil in rice plants growing under drought conditions to boost the resilience of rice to drought. The incorporation of drought-stressed-rice soil with two investigated seaweeds led to improved growth, almost regulated levels of photosynthetic pigments, compatible solutes, MDA, hydrogen peroxide, and phenolic compounds as well as flavonoids, along with notably upregulated expression of PIP1;4, PIP2;7, NCDE5, and OsMyb-R1 genes of the rice cultivars Giza 177 and Giza 179, and this enhanced the water status of rice cultivars grown under drought conditions. Furthermore, this study suggested that amending soil with investigated seaweeds enhanced nutrition and osmolyte production, ameliorated MDA, and upregulated investigated drought-responsive genes as well as promoted the growth along with antioxidant reply thoroughly contribute to improving rice plant tolerance to drought stress.

In the last decade, a lot of research works and reviews have evaluated the effect of LED treatments during the postharvest storage of green vegetables. The curious thing is that, for the same vegetable, some works have shown that LED treatments improve postharvest life, while other researches have shown the opposite. Knowledge of the effects of light on the postharvest metabolism of each vegetable is needed to understand such contradictory results and to develop appropriate applications of postharvest LED technology to improve product quality. In this review, the role of visible light in the regulation of the postharvest senescence of green vegetables will be discussed. The information obtained so far suggests that low-intensity visible light, either continuous or pulsed, can maintain the quality of green tissues after harvest by delaying the onset of senescence and/or by improving their nutritional quality. The results also showed that the effect of LED technology depends on the duration of treatment, the intensity and the quality of the light used, and the type of vegetable irradiated. Studies have shown that both, white and red light, are effective to delay senescence, whereas blue light primarily enhances the antioxidant system with little or no effect in delaying senescence. To date, the published evidence strongly suggests that phytochromes (photoreceptors activated by red light) and phytochrome-interacting factors (PIFs) are involved in the delay of postharvest senescence symptoms.

The regulation of secondary cell wall formation in Arabidopsis thaliana has been extensively studied with NST1, NST2, and NST3 playing key roles in secondary cell wall development in stem, anther, and silique. However, their broader impact on plant growth and development is less understood. This study investigates the phenotypes of T-DNA insertional mutants of NST1 (nst1-1), NST2, NST3 (nst3-1), and the double mutant nst1-1nst3-1 revealing their previously unknown functions in traits crucial for plant fitness. Phylogenetic analysis of the NAC gene family, based on chromosome locations, suggests that local and segmental duplication has expanded the family. NST1, NST2, and NST3 are phylogenetically close, within the same sub-clade, yet located on separate chromosomes, indicating a complex evolutionary history with functional redundancy and diversification. Loss-of-function mutants of NST1, NST2, and NST3 (i.e., nst1-1, nst2, nst3-1, and nst1-1nst3-1) displayed changes in root and hypocotyl length, rosette leaf size and area, stem diameter, vascular bundle structure, stamen characteristics, and silique. The nst3-1 single mutant exhibits the most pronounced defective phenotypes, emphasizing the pivotal role of NST3 in governing various developmental processes. Furthermore, the compounded effects observed in the nst1-1nst3-1 double mutant underscore the intricate interplay between these genes and their collective impact on Arabidopsis growth. Our findings indicate that the function of NST1, NST2, and NST3 genes extends beyond their well-established roles in secondary wall regulation to significantly influence multiple aspects of plant growth and development, enhancing our understanding of their regulatory network in Arabidopsis.

Cowpea (Vigna unguiculata) is a legume crop widely grown in tropical and subtropical regions for human consumption and animal feeding. Despite this importance, drought stress is a major constraint on cowpea production, affecting plant growth, seed quality, and yield. Thus, this study aimed to understand the mechanisms controlling drought tolerance in cowpea. To achieve this goal, two cowpea varieties (Ndout violet pods and Bambey 21) and one mutant line (Me51M4-39M9) were mutagenized using gamma rays. At M6, the seeds of the most productive and vigorous plants were identified, leading to the selection of 33 genotypes. They were sown and grown in the field to develop M7; then, the plants were subjected to drought stress for 38 days at an average daily temperature of 34.5 °C. The analyses focused on physiological parameters such as chlorophyll a and b and total contents and relative water content. In addition, malondialdehyde and proline contents; catalase, ascorbate peroxidase, and superoxide dismutase activities; and the expression of the VunP5CS and VubZip09 genes were quantified. A wide range of variability of relative water content was observed among the mutant lines subjected to drought stress. Chlorophyll a and b and total contents varied under drought but increased in the stay-green genotype (4), while proline content increased significantly in some genotypes such as line 10 but decreased in the other mutant lines under drought. The amount of malondialdehyde decreased in some mutant lines and increased in others under drought stress in comparison to the unstressed control. The activities of catalase and ascorbate peroxidase increased under drought stress in mutant lines 4 (stay green) and 15 (early flowering). Based on the RT-qPCR analysis, proline and the bZIP transcription factor genes were highly expressed under drought in tolerant genotypes 4 and 15. This study revealed that cowpea responds to drought stress through complex processes involving multiple physiological, biochemical, and transcriptomic changes that need to be explored in depth to enhance our understanding of the genetic basis controlling drought tolerance.

Gmelina arborea (G. arborea), a plant of great medicinal as well as socioeconomic importance renowned for its traditional utilization, lacks prior genetic diversity studies specifically in Gujarat, India. Therefore, the present study aimed to delve into the genetic variations within G. arborea across six distinct regions (Kutch, Sabarkantha, Ahmedabad, Rajkot, Panchmahal, and Valsad) in Gujarat. This investigation employed Geographical Information System (GIS) for spatial data evaluation, as well as DNA barcoding technique to corroborate the plant’s authenticity. Leveraging 15 different Inter Simple Sequence Repeats (ISSR) markers facilitated the evaluation of genetic diversity present amongst selected regions. Based on Jaccard’s dissimilarity co-efficient, a cluster analysis has been rendered by applying the Unweighted Pair Group Method with Arithmetic Mean (UPGMA) and Unweighted Neighbour Joining (UNJ) methods. The present study portrayed a significant level of polymorphism of 88% among G. arborea from different regions. The assessment of Polymorphic Information Content (PIC) resulted in a value of 0.42, indicating the presence of compelling genetic variation within these regions. The dendrogram illustrated the genetic relatedness and diversity, with a cophenetic correlation coefficient of 0.9818 (UPGMA) and 0.9962 (UNJ). The accession from the Ahmedabad region stands out as the most diverse, whereas the plant from Panchmahal represents the most primitive genome of all. Notably, this research marks the inaugural and comprehensive genetic assessment of G. arborea from Gujarat, India. These findings provide a valuable foundation for further research and conservation strategies for G. arborea and other medicinal plants.

Graphical Abstract

Chickpea (Cicer arietinum L.) is grown in marginal land with low input and is, therefore, drought-prone. In order to develop a drought-tolerant line, a bi-parental recombinant inbred line (RIL) mapping population was generated by inter-crossing between two varieties JGK3 (ICCV 95334) and Himchana1 (ICCX-810800) having contrasting root traits. Ninety-two genetically diverse RILs of F₈ generation were selected based on their total root length to root dry weight ratio (RL/DW). The leaf relative water content of these RILs under low soil moisture did not show any strong correlation with the RL/DW. Twenty RILs having high RL/DW were evaluated for seed yield in a field under rainfed condition without any supplementary irrigation. The best performing RIL, which performed better than the check varieties, was reevaluated for a further year under rainfed condition. The genotypic constitution of this superior low soil moisture tolerant individual RIL was determined by constructing its recombination map using genome-wide SNPs obtained through genotyping-by-sequencing. The RIL possesses the superior alleles of the genomic QTL region known to govern drought tolerance in chickpea. The phenotypic and genotypic characterization of RILs in our study identified a chickpea pre-breeding line that can be used as a genetic donor for developing drought-tolerant high-yielding chickpea varieties and our results provide an evidence that total root length to root dry weight ratio can be used as a quantitative trait for assessing drought tolerance.

The pathogenic fungus, Alternaria porri (Ellis) Cifferi, that causes purple blotch (PB) disease, is a major constraint to production of onion and allied crops worldwide. In the present study, bulk segregant RNA sequencing (BSR-Seq) was used to analyze onion cultivar Arka Kalyan (resistant parent), Agrifound Rose (susceptible parent), and two sets of their bulks (20 homozygous resistant and 20 susceptible) from F₆ RIL population to identify a potential region for resistance to PB. Transcript profiling resulted in 278.08 million clean reads from 8 libraries. Comparative expression analysis revealed 755 differentially expressed genes (DEGs) including 492 upregulated and 263 downregulated sequences. Bulk frequency ratio (BFR) was estimated between resistant and susceptible bulk, and 2963 common SNPs with BFR > 6 were detected on 1439 transcripts. Euclidean distance association analysis identified a 7.3 Mb resistance specific candidate region in the long arm of chromosome 6. Using RNA-Seq, 23 DEGs were reported in the candidate region in chromosome 6, including ACCL_20794 (Chr6: 187,639,724–187,643,297), a disease-resistant protein of the CC-NBS-LRR class, whose expression was elevated in the resistant pools following PB treatment. The ACCL_20794 gene was cloned and based on the sequences from the two parents, a single amino acid mutation—histidine (H) to serine (S) was detected in the resistance genotype Arka Kalyan. Quantitative reverse transcription (qRT)-PCR further demonstrated significantly differential expression of ACCL_20794 in the two parents as well as the RIL bulks. This indicates that ACCL_20794 might be the candidate resistance gene ApR1 and is implicated in the PB resistance response.

Developing C₄ rice is one of the global research challenges for yield improvement. In the optimal environment, the key difference between C₃ and C₄ plants with reference to biomass accumulation is photorespiration. Photorespiration is important for a plant’s survival. In spite of the high energy cost and carbon loss, diversion of a significant part of carbon from photorespiration to enrich CO₂ concentration (preventing carbon loss) was opted for. Installation of photorespiratory bypasses was reported to improve biomass and yield in C₃ plants. The contribution of non-foliar photosynthesis to yield improvement was well documented. However, its underlying genetic differences, when compared to foliar photosynthesis, are a research gap. In three rice genotypes (APO, BAM4234, and CROSSA), we compared the expression levels (for genes associated with photosynthesis and photorespiration) between the photosynthetic non-foliar (3–5-day old developing grains and peduncle) and foliar (flag leaf) organs to understand their differential expression pattern using an RNA-seq approach. Significant downregulation of the genes of photorespiration was observed in non-foliar photosynthetic tissue (3–5 dpa old developing grains) when compared to the flag leaves. Simultaneously, our study also revealed significant upregulation of the chloroplastic pyruvate dehydrogenase (cpPDC, BGIOSGA015796) gene in developing grains, when compared to the flag leaf, in all three genotypes. The occurrence of an in planta photorespiratory bypass in the photosynthetic tissues of the developing grains in rice is proposed. Enhanced expression levels for the cpPdc gene in the foliar tissues will potentially install a photorespiratory bypass for enhanced biomass accumulation and thereby yield.

In Thailand, all Thai-certified varieties of mungbean [Vigna radiata (L.) R. Wilczek] preferentially grown by farmers are susceptible to powdery mildew (PM) disease. Marker-assisted gene pyramiding (MAGP) for improving resistant varieties is a sustainable strategy to overcome its outbreak in mungbean fields. In this study, two PM resistance genes from donor parent A2 were pyramided into the Thai-certified variety, namely Suranaree University of Technology 1 (SUT1) using marker-assisted backcrossing (MABC). Three polymorphic marker loci linked to PM resistance genes and three marker sets with 72 polymorphic loci were subsequently used for foreground and background selection, respectively. As a consequence, three pyramided BC₄ lines B1, B2, and D5, carrying all foreground marker loci in homozygosity, were obtained. Their recurrent parent genome (RPG) recovery was 100.0%, 100.0%, and 98.8% for background marker Sets A, B, and C, respectively. In field conditions, it was found that a low level of PM severity was exhibited in the pyramided BC line D5, which also had most of the agronomic traits similar or superior to SUT1. Moreover, the yield performance of this line was higher than SUT1, by up to 8.3–12.2%, during PM outbreaks or in the absence of disease. Thus, this pyramided BC line can be further used to develop a new resistant variety for farmers in the future.

The present investigation systematically examined the distribution of 5S and 45S rDNA sites in six distinct Fritillaria species, all characterized as diploid with 2n = 2x = 24 chromosomes. Fritillaria assyriaca ecotypes displayed variable numbers of B chromosomes (Bs), ranging from one to four, while F. zagrica exhibited two additional B chromosomes. Terminal or sub-terminal chromosomal regions harbored one to two pairs of 5S rDNA sites. Regarding 45S rDNA sites, F. raddeana featured a singular pair, F. assyriaca, F. zagrica, and F. persica exhibited three pairs, F. avromanica presented four pairs, and F. chlorantha displayed eight pairs, predominantly situated distally, except for F. raddeana and F. chlorantha, which demonstrated interstitial and sub-terminal locations, respectively. Chromosome and karyotype indices facilitated the identification of, F. avromanica and F. chlorantha as species with the most symmetrical and asymmetrical chromosomes, respectively. Cluster analysis of the karyotype similarity matrix revealed incongruities between the observed number and distribution of rDNA sites and the established taxonomic classifications, particularly notable in F. chlorantha within the Fritillaria subgenus. The results provide significant insights into the genetic diversity and karyotype characteristics of Fritillaria, challenging conventional taxonomic frameworks. The observed variations in the numbers and locations of rDNA sites underscore the necessity for a nuanced understanding of genetic relationships within the Fritillaria subgenus.