Physiology and Molecular Biology of Plants最新文献

Banana streak disease was identified as a new threat to banana cultivar Virupakshi (syn: Hill banana, AAB), registered under Geographical Indications (G.I. 124) in India. PCR and rolling circle amplification (RCA) of infected leaf samples revealed the presence of banana streak GF virus (BSGFV) as the causative agent of streak symptoms. RCA and sequence analysis identified an episomal BSGFV variant (BSGFV-IN; MW389538) along with the full-length BSGFV genome (BSGFV-IN1; PP134844). The shorter BSGFV-IN genome measured 6590 bp with a deletion of 673 bp, while the full-length BSGFV-IN1 genome was 7263 bp. Sequencing of the cloned fragments using MinION nanopore sequencer further confirmed these findings, with both isolates showing > 99% sequence similarity to the BSGFV (AY493509) from Ecuador. Interestingly, BSGFV-infected tissue-cultured (TC) plants exhibited variation in streak symptom expression under different climatic conditions. At lower temperatures (below 25 °C), typical streak symptoms were prevalent, whereas at higher temperatures, the symptoms completely remitted. This is the first documented report of the natural co-existence of a novel episomal BSGFV variant with a shorter genome, along with the full-length genome, associated with streak symptoms in cv. Virupakshi from India.

Supplementary information: The online version contains supplementary material available at 10.1007/s12298-025-01546-w.

Petal senescence represents a crucial phase in the developmental continuum of flowers, ensuing tissue differentiation and petal maturation, yet anteceding seed formation and development. Instigation of petal senescence entails myriad of changes at the cytological, physiological and molecular dimensions, mirroring the quintessential characteristics of cell death. In the current investigation biochemical and molecular intricacies were scrutinized across various developmental stages (bud to the senescent phase). Scanning electron microscopy analysis unveiled significant changes in petal tissue morphology, evolving from tightly interwoven ridges and grooves at the bud stage to a completely flattened surface devoid of intricate patterns in the senescent stage. Throughout the developmental continuum, significant metabolic reconfigurations were discerned. The concentration of soluble proteins displayed a continuous decrement from the bud phase through the anthesis stage, culminating in a pronounced diminution during the senescent phase. This pattern was concomitant with the expression profiles of RaSAG12 (senescence-associated gene 12) and RaDAD1 (defender against cell death 1) genes. Membrane integrity exhibited a gradual decline from the bud to the open stage, attributed to diminished lipoxygenase (LOX) activity and low RaLOX1 (lipoxygenase 1) transcript levels. This deterioration was further exacerbated during senescence by increased LOX1 expression, ultimately compromising membrane stability. The developmental progression of Ranunculus asiaticus flowers is modulated by hormonal flux, with abscisic acid and ethylene concentrations escalating as senescence approaches. This upsurge is attributed to elevated mRNA transcripts of RaAAO3 (abscisic aldehyde oxidase 3) and RaACO (1-amino cyclopropane-1- carboxylic acid oxidase), concomitant with a reduction in RaIPT3 (isopentenyl transferase 3) transcript abundance during the senescent phase compared to earlier developmental phases. ROS (Reactive oxygen species) neutralizing antioxidant enzymes exhibited a marked increase from the bud to the bloom stage, leading to reduced hydrogen peroxide (H₂O₂) levels. However, during the senescent phase, the activity of these enzymes diminished markedly, resulting in the accumulation of ROS and ensuing oxidative damage.

The consequences of walnut (Juglans regia L.) leaf scorch (WLS) were studied using the cultivated varieties, Wen185 (Juglans regia 'Wen 185') and Xinxin2 (Juglans regia 'Xinxin2') in the Aksu region, Xinjiang, China. Photosynthetic parameters and indoor chemical analysis were used to determine the variations in photosynthetic characteristics, osmotic regulatory substances, antioxidant enzyme activities, and changes in fruit yield and quality between diseased and healthy leaves. Net photosynthetic rate (P _n) and stomatal conductance (G _s) of Xinxin2 diseased leaves were lower and intercellular CO₂ concentration (C _i) was higher than in healthy leaves. P _n, G _s, and C _i of Wen185 leaves were lower than those of healthy leaves initially. During the peak stage of disease, P _n and G _s of Wen185 were lower, whereas C _i was higher than in healthy leaves. The initial fluorescence (F ₀) of diseased leaves was higher and the maximum photochemical efficiency of photosystem II (PSII, F _v/F _m) was lower. The decrease in F _v/F _m of diseased Wen185 leaves was smaller than in Xinxin2. Malondialdehyde (MDA) content in Wen185 and Xinxin2 diseased leaves was higher than in healthy leaves. From late June to mid-July, the superoxide dismutase (SOD) activity and soluble protein (SP) content in the diseased leaves were higher than in healthy leaves, becoming lower in late August. Plant yield, single fruit dry weight, fruit longitudinal diameter, fruit shape index, kernel extraction rate, fat content, and protein content of the diseased plants were lower. Single fruit fresh weight, fruit transverse diameter, and fruit lateral diameter in Wen185 plants were similar but differed in diseased Xinxin2 plants. WLS reduces carbon assimilation and PSII reaction center activity leading to intensified membrane lipid peroxidation, gradual imbalance of osmotic regulation homeostasis, and decreased antioxidant capacity.

Auxin response factors (ARFs) are important transcription factors that regulate the expression of auxin response genes, thus play crucial roles in plant growth and development. However, the functions of ARF genes in bermudagrass (Cynodon dactylon L.), a turfgrass species of great economic value, remain poorly understood. In this study, a total of 86 CdARF genes were identified from the C. dactylon genome and were categorized into five groups according to their phylogenetic relationships. The five groups of CdARF genes exhibited specific gene structure and protein domain characteristics, and showed distinct gene expression patterns in different organs, wild accessions and under different stress treatments. Among the 86 CdARF genes, the CdARF6-B2 gene encoded an N-terminally truncated group V ARF protein with high sequence similarity to AtARF2 and OsARF24. The CdARF6-B2 gene was highly expressed in the aboveground vegetative organs (leaf, shoot and stolon) and weakly expressed in the root. The CdARF6-B2 protein was localized in the nucleus but showed no transactivation activity, although its middle region had a strong transactivation activity. Ectopic expression of CdARF6-B2 inhibited the vegetative growth of transgenic Arabidopsis plants possibly through down-regulating the expression of auxin transport-related PIN3 gene and impeding the polar transport of auxin. These results not only established solid foundations to characterize the regulatory mechanism of auxin signaling in the growth and development of bermudagrass but also provided new insights into the function of ARF genes in plants.

Supplementary information: The online version contains supplementary material available at 10.1007/s12298-024-01538-2.

Following the identification of the self-compatibility gene (Sli) in diploid potatoes two decades ago, the breeding of inbred based diploid hybrid potatoes made its way. Tetraploid potatoes have a long history of cultivation through domestication and selection. Tetrasomic inheritance, heterozygosity and clonal propagation complicate genetic studies, resulting in a low genetic gain in potato breeding. Diploid hybrid TPS potato breeding, similar to the developments in hybrid maize, was pursued as an alternative to the genetic improvement of potatoes. However, several challenges, like self-incompatibility and high inbreeding depression associated with diploid potatoes, must be overcome to develop inbred lines in potatoes. Moreover, the inbred lines must retain good fertility and vigour for hybrid breeding. Good progress has been made by creating di-haploids of popular varieties, mapping self-incompatibility inhibitor gene, understanding the genetic basis of inbreeding depression, and identifying genomic regions for deleterious alleles and fertility. Further, the genome sequencing of diploid inbred lines has revealed the genetics of key traits associated with potato breeding. This article discussed these insights and summarized the progress of diploid hybrid TPS potato breeding. Recent advances in genetic and genomic research and genome editing technology have shown promise for this technology's success and far-reaching implications.

DNA methylation is a paramount epigenetic mark that helps balance gene expression post-transcriptionally. Its effect on specific genes determines the plant's holistic development and acclimatization during adversities. Triticum aestivum L., an allohexaploid, is a dominant cereal crop with a large genome size. Changing environmental conditions exert a profound impact on its overall yield. Here, bibliometric science mapping was employed for a nuanced understanding of the prevailing research trends in the DNA methylation study of wheat. The detailed data obtained was used to delve deep into its fundamentals, patterns and mechanism of action, to accumulate evidence of the role of DNA methylation in the regulation of gene expressions across its entire genome. This review encapsulates the methylation/demethylation players in wheat during different stages of development. It also uncloaks the differential methylation dynamics while encountering biotic and abiotic constraints, focusing on the critical function it plays in fostering immunity. The study significantly contributes to broadening our knowledge of the regulatory mechanism and plasticity of DNA methylation in wheat. It also uncovers its potential role in improving breeding programs to produce more resilient wheat varieties, stimulating further research and development in the field.

Supplementary information: The online version contains supplementary material available at 10.1007/s12298-024-01539-1.

Given the rising population and food demand, it is imperative to devise solutions to enhance plant resilience against abiotic stresses. Salinity stress impacts plant growth but also hampers plant performance and productivity. Plant hormones have emerged as a viable remedy to mitigate the detrimental effects of salinity stress on plants. This study delved into the molecular investigation of the impact of 24-Epibrassinolide (EBL) on Okra plants (Abelmoschus esculentus L.) under two levels of salinity stress (75 and 150 mM), scrutinizing morphological, biochemical, and physiological parameters. Salinity stress led to a decline in growth, pigment and protein content, with EBL application ameliorating these indicators, albeit insignificantly impacting protein levels. Salinity triggered an upsurge in soluble sugars, proline, antioxidant enzymes (CAT, SOD, GP, and APX), and sodium levels, while reducing potassium and micronutrient concentrations (copper, iron, zinc). It downregulated the expression of NHX1, NHX4, SOS1, SOS2, and SOS3 genes. EBL treatment bolstered potassium and micronutrient uptake, upregulated gene expression and enzymatic antioxidants, and elevated soluble sugar and proline levels. Analysis of the outcomes across these parameters suggests that EBL holds promise as an effective agent in mitigating salinity stress in Okra plants.

The rapid growth of Bamboo made the uptake and allocation of nitrogen much important. Nitrate is the main form that plant utilized nitrogen by nitrate transporters (NRTs) as well as ammonium salt. In this study, we identified 155 DfNRT genes which mapped to 32 chromosomes out of 35 chromosomes in Dendrocalamus farinosus. Collinearity analysis showed most NRT genes in D. farinosus paired with NRT genes in D. farinosus and P. edulis, which another two sequenced woody bamboo species, and the divergence was similar to the woody bamboo whole-genome duplication event. Through the ¹⁵N-nitrate trace analysis, we found that the nitrogen absorbed by roots in D. farinosus was preferentially distributed to above-ground parts, especially transported to leaves. DfNPF2.13 and DfNPF6.9 exhibited higher expression in leaf, and upregulated with extra N supply, suggesting they might be participating in N allocation between leaves in D. farinosus. This study provides a foundation for understanding the mechanism of nitrate transport and distribution in bamboo, and provide valuable information for improving bamboo nitrate absorption and promoting efficient nitrogen utilization.

Supplementary information: The online version contains supplementary material available at 10.1007/s12298-024-01541-7.

Alanine aminotransferase (AlaAT) is a crucial enzyme present in various isoforms. It is playing vital role in both humans and plants. This concise review focuses on the role of AlaAT in plants, particularly on preharvest sprouting, hypoxia, nitrogen use efficiency, abiotic and biotic stress tolerance. The molecular genetics of AlaAT, including gene identification and the impact on plant yield and its physiology, is discussed. Notably, the major dormancy gene Qsd1/SD1 governing AlaAT synthesis has been characterized and cloned in various crops. This review emphasizes the current understanding of AlaAT and its influence on plants, covering mechanisms regulating preharvest sprouting, hypoxia, drought tolerance, salt tolerance, biotic resistance and nitrogen use efficiency. Identifying a protein with multidimensional roles in crop plants is very important. Modern biotechnological approaches can alter such candidate gene/protein for superior varieties development. Overall, the review gives an understanding of the uncovered area of AlaAT and the challenge of climatic change triggers in plants. In the future, the potential of genome editing in AlaAT through enhancer insertion and rapid stabilization through speed breeding will impart resilience to crop plants against climate change.

Hexaploid Echinochloa. crus-galli var. crus-galli and tetraploid E. crus-galli var. oryzicola are major weeds in rice fields. Supplementing molecular marker data with morphological and morphometric characterization is considered a reliable method for species identification. In the present study, Echinochloa weed accessions were collected from rice fields in Tamil Nadu, India [as plants (12) or seeds (10)]. Species level identification was carried out using the distinguishing chloroplastic DNA marker, trnT-L. Eight accessions were identified as E. crus-galli consistently across T₀ and T₁ generations and twelve others over a single generation (T₀ or T₁). Spikelet length is an important feature used to distinguish E. crus-galli and E. oryzicola. Accession P1, identified as E. oryzicola, using a chloroplast DNA marker (trnT-L insertion), has a spikelet length more consistent with E. crus-galli (≤ 4 mm) than E. oryzicola. Thus, 'inconsistent' accession P1 may have inherited DNA paternally from E. oryzicola, instead of the unknown maternal donor usually reported in literature for E. crus-galli. We also report, for the first time, the occurrence of heteroplasmic variation in Echinochloa (accession D4) over two successive generations (T₀ and T₁). We also suggest a caveat in the use of morphometric spikelet characters and chloroplastic DNA marker data alone to classify Echinochloa weed species conclusively. Occurrence of paternal plastid inheritance and heteroplasmy may have implications on weed fitness, including range expansion and selective advantage(s) in a rapidly changing environment (herbicide or stress tolerance).

Supplementary information: The online version contains supplementary material available at 10.1007/s12298-024-01525-7.