Turning the Knobs: The Impact of Post-translational Modifications on Carbon Metabolism

Plants rely on the carbon fixed by photosynthesis into sugars to grow and reproduce. However, plants often face non-ideal conditions caused by biotic and abiotic stresses. These constraints impose challenges to managing sugars, the most valuable plant asset. Hence, the precise management of sugars is crucial to avoid starvation under adverse conditions and sustain growth. This review explores the role of post-translational modifications (PTMs) in the modulation of carbon metabolism. PTMs consist of chemical modifications of proteins that change protein properties, including protein-protein interaction preferences, enzymatic activity, stability, and subcellular localization. We provide a holistic view of how PTMs tune resource distribution among different physiological processes to optimize plant fitness.

Genome-wide identification and expression analysis of the cucumber PYL gene family

Abscisic acid (ABA) is a very important hormone in plants. It regulates growth and development of plants and plays an important role in biotic and abiotic stresses. The Pyrabactin resistance 1-like (PYR/PYL) proteins play a central role in ABA signal transduction pathways. The working system of PYL genes in cucumber, an important economical vegetable (Cucumis sativus L.), has not been fully studied yet. Through bioinformatics, a total of 14 individual PYL genes were identified in Chinese long ‘9930’ cucumber. Fourteen PYL genes were distributed on six chromosomes of cucumber, and their encoded proteins predicted to be distributed in cytoplasm and nucleus. Based on the phylogenetic analysis, the PYL genes of cucumber, Arabidopsis, rice, apple, Brachypodium distachyon and soybeancould be classified into three groups. Genetic structures and conserved domains analysis revealed that CsPYL genes in the same group have similar exons and conserved domains. By predicting cis-elements in the promoters, we found that all CsPYL members contained hormone and stress-related elements. Additionally, the expression patterns of CsPYL genes were specific in tissues. Finally, we further examined the expression of 14 CsPYL genes under ABA, PEG, salt stress. The qRT-PCR results showed that most PYL gene expression levels were up-regulated. Furthermore, with different treatments about 3h, the relative expression of PYL8 was up-regulated and more than 20 times higher than 0h. It indicated that this gene may play an important role in abiotic stress.

Advances in 5-Aminolevulinic Acid Priming to Enhance Plant Tolerance to Abiotic Stress

Priming is an adaptive strategy that improves plant defenses against biotic and abiotic stresses. Stimuli from chemicals, abiotic cues, and pathogens can trigger the establishment of priming state. Priming with 5-aminolevulinic acid (ALA), a potential plant growth regulator, can enhance plant tolerance to the subsequent abiotic stresses, including salinity, drought, heat, cold, and UV-B. However, the molecular mechanisms underlying the remarkable effects of ALA priming on plant physiology remain to be elucidated. Here, we summarize recent progress made in the stress tolerance conferred by ALA priming in plants and provide the underlying molecular and physiology mechanisms of this phenomenon. Priming with ALA results in changes at the physiological, transcriptional, metabolic, and epigenetic levels, and enhances photosynthesis and antioxidant capacity, as well as nitrogen assimilation, which in turn increases the resistance of abiotic stresses. However, the signaling pathway of ALA, including receptors as well as key components, is currently unknown, which hinders the deeper understanding of the defense priming caused by ALA. In the future, there is an urgent need to reveal the molecular mechanisms by which ALA regulates plant development and enhances plant defense with the help of forward genetics, multi-omics technologies, as well as genome editing technology.

Integrated Metabolomic and Transcriptomic Analysis of the Anthocyanin and Proanthocyanin Regulatory Networks in Red Walnut Natural Hybrid Progeny Leaves

BackgroundWalnuts are one of the most important dry fruit crops worldwide, typically exhibiting green leaves and yellow–brown or gray–yellow seed coats. A specific walnut type, red walnut ‘RW-1’, with red leaves and seed coats was selected as the plant material because of its higher anthocyanin and proanthocyanin (PA) contents. Anthocyanins and PAs coprise important secondary defense methods for plants to respond to biotic and abiotic stresses. However, few studies have focused on the molecular mechanism of anthocyanin biosynthesis in walnuts.ResultsFrom the results of widely targeted metabolome and anthocyanidin detection analysis, 395 substances, including 4 PAs and 26 anthocyanins, were identified from the red-leaf walnuts of RW-1 natural hybrid progenies (SR) and the green-leaf walnuts of RW-1 natural hybrid progenies (SG). Among these, all anthocyanin types in SR were significantly upregulated compared with SG. Additionally, delphinidin 3-O-galactoside, cyanidin 3-O-galactoside, delphinidin 3-O-glucoside and cyanidin 3-O-glucoside were identified as the primary components of anthocyanidins because of their higher contents. Nine anthocyanidins, malvidin 3-O-galactoside, malvidin 3-O-arabinoside, cyanidin 3-O-(6-O-malonyl-beta-D-glucoside), delphinidin 3-O-glucoside, delphinidin 3,5-O-diglucoside (Delphin), peonidin 3-O-(6-O-malonyl-beta-D-glucoside), petunidin 3-O-(6-O-malonyl-beta-D-glucoside), petunidin 3-O-arabinoside and pelargonidin 3-O-(6-O-malonyl-beta-D-glucoside), were detected only in the SR walnuts. For PAs, proanthocyanin C1 was upregulated in SR compared with SG, while proanthocyanin B1 and proanthocyanin B3 were upregulated in SR-1 and SR-3 but downregulated in SR-2 compared with the controls. Furthermore, transcriptome analysis demonstrated that the expression of structural genes (C4H, F3H, F3’5’H, UFGTs, LAR and ANR), four MYBs and six WD40s in the anthocyanin and PA biosynthetic pathways were significantly higher in the SR walnut.ConclusionsOur results provide valuable information on anthocyanin and PA metabolites and candidate genes in anthocyanin and PA biosynthesis, which provides new insights into anthocyanin and PA biosynthesis in walnuts.

Integrating Wheat Nucleolus Structure and Function: Variation in the Wheat Ribosomal RNA and Protein Genes

We review the coordinated production and integration of the RNA (ribosomal RNA, rRNA) and protein (ribosomal protein, RP) components of wheat cytoplasmic ribosomes in response to changes in genetic constitution, biotic and abiotic stresses. The components examined are highly conserved and identified with reference to model systems such as human, Arabidopsis, and rice, but have sufficient levels of differences in their DNA and amino acid sequences to form fingerprints or gene haplotypes that provide new markers to associate with phenotype variation. Specifically, it is argued that populations of ribosomes within a cell can comprise distinct complements of rRNA and RPs to form units with unique functionalities. The unique functionalities of ribosome populations within a cell can become central in situations of stress where they may preferentially translate mRNAs coding for proteins better suited to contributing to survival of the cell. In model systems where this concept has been developed, the engagement of initiation factors and elongation factors to account for variation in the translation machinery of the cell in response to stresses provided the precedents. The polyploid nature of wheat adds extra variation at each step of the synthesis and assembly of the rRNAs and RPs which can, as a result, potentially enhance its response to changing environments and disease threats.

Screening of Lentil Genotypes against Highly Aggressive Strain of Fusarium oxysporum f. sp. lentis

Lentil is one of the most nutritious pulse crops known as masur and grown as a rainfed crop throughout the world in winter season. It is rich in protein, starch, micronutrients and dietary fiber. In the global scenario, India ranked first in the area and second in the production with Bihar being one the major lentil growing state. The majority of the lentil crop is grown in Tal area of the state. As it is cultivated as a rainfed crop, it gets severely affected by several biotic and abiotic stresses. Among the biotic stresses, Fusaium wilt, caused by Fusarium oxysporum f. sp. lentis (Fol) is one of the major fungal diseases and remarkably causing severe crop damage from vegetative to reproductive stage producing significant yield reduction. Fol isolate exhibit great variability and aggressiveness based on agro- climatic conditions. AGLF-11 isolate of Fol collected from Tal area of Bihar was found to be highly aggressive based on previous studies. For this, 50 diverse genotypes were screened against this isolate under greenhouse condition, out of which 14 genotypes showed high susceptibility, 29 genotypes showed moderate susceptibility, 5 genotypes exhibited moderately resistance and only 2 genotypes (L 7920 and DPL 58) exhibited resistance reaction.

Harnessing Trichoderma in Agriculture for Productivity and Sustainability

Increased agricultural activities driven by rising food demand have led to environmental problems mostly arising from the high levels of external inputs and resources that are required. Additionally, environmental changes, such as global warming, can lead to various biotic and abiotic stresses, which have negative impacts on crop production. Numerous solutions and agricultural strategies have been introduced to overcome these problems. One of the ways to improve plant production as well as to increase resistance towards biotic and abiotic stresses is by utilizing beneficial microbes as soil inoculants. A better understanding of the ability of Trichoderma to enhance crop production and the mechanisms that are involved are important for deriving maximum benefits from their exploitation. These versatile fungi hold great promise for the development of viable commercial products that can be used widely in agriculture for increasing crop productivity in a more sustainable way. Many previous reviews on Trichoderma have tended to focus on the mechanisms of Trichoderma in enhancing plant growth and yield. This current review discusses the sustainability aspect of using Trichoderma as plant growth regulators, the impact on plant growth and yield as well as their effects in regulating biotic and abiotic stresses.

PHYTHORMONES AND ABIOTIC STRESS (REVIEW)

Plants experience a variety of biotic and abiotic stresses that cause crop losses worldwide. Preventing crop losses due to these factors is of particular importance. For this, it is important to understand the mechanisms of both suppressing and stimulating seed germination and to develop technologies for controlling seed dormancy and development in order to avoid unwanted germination in the ears. Gene switching technologies can be used to address this and similar problems in seed development. Recent studies have shown that classical phytohormones - auxins, cytokinins, abscisic acid, ethylene, gibberellins - control all stages of plant ontogenesis. In addition to the classic phytohormones, there are relatively new ones - brassinosteroids, jasmonates, strigolactones, salicylates, which deserve consideration in a separate review. Together, these compounds are important metabolic engineering targets for the production of stress-resistant crops. In this review, we have summarized the role of phytohormones in plant development and resistance to abiotic stresses. Experimental data were presented on the transport of phytohormones, the interaction between them, as a result of which the activity of a certain hormone can be either enhanced or suppressed. We have identified the main links of phytohormones with an emphasis on the response of plants to abiotic stresses and have shown that the effect of an individual hormone depends on the ratio with other phytohormones and metabolites. Additional research along these lines will help explain different stress responses and provide tools to improve plant stress tolerance.

Efficient Exploration of Silicon Derived Benefits to Combat Biotic and Abiotic Stresses in Fruit Crops

Silicon (Si) is the most abundant element after oxygen on the earth crust surface. It plays essential role in crop production by stimulating the growth and development. Very substantial efforts have been performed to better explore Si derived benefits for horticulture crops. In the present review, molecular and physiological mechanisms explaining the observed beneficial effects plant derive from the Si supplementations, more particularly in horticultural species have been discussed. In general, horticulture crops need extensive management and higher crop protection measures compared to agronomical crops. Therefore, integrated approaches including Si supplementations will help to improve plant resilience under biotic and abiotic stresses. Application of Si to plants promotes cell walls strength and provides additional support through increased mechanical and biochemical support. Horticultural crop production is frequently subjected to the naturally occurring different biotic and abiotic stresses that can substantially reduce the absorption and translation of essential elements and ultimately decrease the crop yield. Fruit and vegetable production in Drought, salinity, high and low temperature, toxic metals and pest infection prone areas is the key to meet the world minimum nutrients demand. Here, molecular mechanism involved in the Si uptake by root and subsequent transport to areal tissues is also illustrated. However, Si uptake mechanism at molecular level poorly studied in horticulture crops. Here we described the role of Si and its transporters in mitigating abiotic stress condition in horticultural plants.