Plant Science最新文献

Cold stress represents one of the major constraints for agricultural systems and crops productivity, inducing a wide range of negative effects. Particularly, long-term cold stress affects lipid metabolism, modifying the lipids/proteins ratio, the levels of phospholipids and glycolipids, and increasing lipids’ unsaturation in bio-membranes. Glucose-6-phosphate dehydrogenase (G6PDH) reported prominent roles as NADPH suppliers in response to oxidative perturbations. Cytosolic G6PDH was suggested as the main isoform involved in cold stress response, while a down-regulation of the chloroplastic P1-G6PDH was observed. We thus investigated an Arabidopsis mutant defective for the P1-G6PDH (KO-P1) using integrated approaches to verify a possible role of this isoform in low temperature tolerance. KO-P1 genotype showed an improved tolerance to cold stress, highlighting a better photosynthetic efficiency, a reduction in stress markers content and a different regulation of genes involved in stress response. Intriguingly, the lack of P1-G6PDH induced modification in the levels of the main fatty acid and lipid species affecting the morphology of chloroplasts and mitochondria, which was restored under cold. Globally, these results indicate a priming effect induced by the absence of P1-G6PDH able to improve the tolerance to abiotic stress. Our results suggest novel and specific abilities of P1-G6PDH, highlighting its central role in different aspects of plant physiology and metabolism.

Soil salinization leads to reduced crop yields and waste of land resources, thereby impacting global food security. To meet the increasing demand for food and simultaneously alleviate pressure on soil resources, the development of sustainable agriculture is imperative. In contrast to physical and chemical methods, bioremediation represents an efficient and environmentally friendly approach. Fungal symbionts have been found to be associated with most plants in natural ecosystems, colonizing and residing within the internal tissues of host plants. Moreover, the potential of fungal symbionts in improving saline-alkaline soil has been widely recognized and confirmed. Numerous reports have documented the effectiveness of arbuscular mycorrhizal fungi in alleviating salt stress in plants. Meanwhile, research on other endophytic fungi for mitigating plant salt stress has emerged in recent years, which contributes to refining mechanisms for enhancing plant salt tolerance. In this review, we summarized various mechanisms by which endophytic fungi enhance plant salt tolerance. We also provided an overview of the challenges and development directions in the field of fungal symbiosis, with the aim of offering a viable strategy for the bioremediation of saline-alkali soils.

The continuous change in climate, along with irregular rainfall patterns, poses a significant threat to sustainable agricultural productivity worldwide. Both high temperatures and drought stress are key factors limiting crop growth, and with global climate change, the occurrence of combined heat and drought stress is expected to rise. This will further exacerbate the vulnerability of agricultural yield. Simultaneous heat and drought stress is prevalent in field conditions, and while extensive research has been done on the individual effects of heat and drought stress on plants, little is known about the molecular mechanisms underlying plant acclimation to a combination of these stressors. The reproductive stage, especially the flowering phase, has been identified as the most sensitive to both heat and drought stress, leading to sterility in plants. However, our understanding of the combined stress response in commonly used crop plants is still limited. Hence, it is crucial to study and comprehend the effects and interactions between high temperatures and drought stress during the reproductive stages of crops. This review delves into the morpho-physiological changes in reproductive organs of various plant species under combined heat and drought stress and also details the molecular regulation of the mechanism of combined stress tolerance in plants. Notably, the article incorporates expression analyses of candidate genes in rice flowers, emphasizing the utilization of modern biotechnological methods to enhance stress tolerance in plants. Overall, the review provides a comprehensive insight into the regulation of floral development in plants following concurrent heat and drought stress.

Gibberellic acids (GAs) are a group of endogenous phytohormones that play important roles in plant growth and development. SLENDER RICE (SLR) serves as a vital component of the DELLA gene family, which plays an irreplaceable role in regulating plant flowering and height, as well as stress responses. SLR gene has not been reported in mango, and its function is unknown. In present study, two DELLA subfamily genes MiSLR1 and MiSLR2 were identified from mango. MiSLR1 and MiSLR2 were highly expressed in the stems of the juvenile stage, but were expressed at a low level in flower buds and flowers. Gibberellin treatment could up-regulate the expression of MiSLR1 and MiSLR2 genes, but gibberellin biosynthesis inhibitor prohexadione-calcium (Pro-Ca) and paclobutrazol (PAC) treatments significantly down-regulated the expression of MiSLR1, while MiSLR2 was up-regulated. The expression levels of MiSLR1 and MiSLR2 were up-regulated under both salt and drought treatments. Overexpression of MiSLR1 and MiSLR2 genes significantly resulted early flowering in transgenic Arabidopsis and significantly up-regulated the expression levels of endogenous flower-related genes, such as SUPPRESSOR OF CONSTANS1 (SOC1), APETALA1 (AP1), and FRUITFULL (FUL). Interestingly, MiSLR1 significantly reduced the height of transgenic plants, while MiSLR2 gene increased. Overexpression of MiSLR1 and MiSLR2 increased seed germination rate, root length and survival rate of transgenic plants under salt and drought stress. Physiological and biochemical detection showed that the contents of proline (Pro) and superoxide dismutase (SOD) were significantly increased, while the contents of malondialdehyde (MDA) and H₂O₂ were significantly decreased. Additionally, protein interaction analysis revealed that MiSLR1 and MiSLR2 interacted with several flowering-related and GA-related proteins. The interaction between MiSLR with MiGF14 and MiSOC1 proteins was found for the first time. Taken together, the data showed that MiSLR1 and MiSLR2 in transgenic Arabidopsis both regulated the flowering time and plant height, while also acting as positive regulators of abiotic stress responses.

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  With the rapid development of new breeding techniques, the ecological impacts of transgenic plants receive wide concern again, particularly for potential gene flow from transgenic crops to their relatives. The transgene insertion position, number of gene copies, and flanking sequence of exogenous genes integrated into the recipient genome affect the genetic stability and fitness of offspring.

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  We employed hybrids F₁ and F₂, six backcross generations BC₁-BC₆ and BC₁F₁ from transgenic Brassica napus with Bacillus thuringiensis (Bt) cry1Ac gene and its wild relative B. juncea through hand pollination. We detected exogenous gene copies, mRNA transcription, and protein expression by ddPCR, qRT-PCR and ELISA, and the fitness of hybrid and backcross generations.

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  Exogenous genes followed Mendelian segregation expectations in hybrid and backcrossed generations, with stable gene copies, mRNA transcription and protein concentration of exogenous genes in offspring. Exogenous gene copies had no significant effects on plant fitness, but had positive effects on mRNA transcription and protein concentration that varied with growth stages in hybrid and backcross generations.

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  Our study demonstrated inheritance and ecological effects of exogenous genes from transgenic plants to wild relatives, which will help ecological risk management of biotechnological plants released in the nature.

Fleshy fruit metabolism is intricately influenced by environmental changes, yet the hormonal regulations underlying these responses remain poorly elucidated. ABA and ethylene, pivotal in stress responses across plant vegetative tissues, play crucial roles in triggering fleshy fruit ripening. Their actions are intricately governed by complex mechanisms, influencing key aspects such as nutraceutical compound accumulation, sugar content, and softening parameters. Both hormones are essential orchestrators of significant alterations in fruit development in response to stressors like drought, salt, and temperature fluctuations. These alterations encompass colour development, sugar accumulation, injury mitigation, and changes in cell-wall degradation and ripening progression. This review provides a comprehensive overview of recent research progress on the roles of ABA and ethylene in responding to drought, salt, and temperature stress, as well as the molecular mechanisms controlling ripening in environmental cues. Additionally, we propose further studies aimed at genetic manipulation of ABA and ethylene signalling, offering potential strategies to enhance fleshy fruit resilience in the face of future climate change scenarios.

Plant architecture is an important agronomic trait to determine the biomass and sward structure of forage grass. The IGT family plays a pivotal role in plant gravitropism, encompassing both the gravitropic response and the modulation of plant architecture. We have previously shown that LjLAZY3, one of the IGT genes, plays a distinct role in root gravitropism in L. japonicus. However, the function of LAZY proteins on shoot gravitropism in this species is poorly understood. In this study, we identified nine IGT genes in the L. japonicus genome, which have been categorized into four clades based on the phylogenetic relationships of IGT proteins from 18 legumes: LAZY1, NGR (NEGATIVE GRAVITROPIC RESPONSE OF ROOTS), IGT-LIKE, and TAC1. We found that LAZY genes in the first three clades have demonstrated distinct role for modulating plant gravitropism in L. japonicus with specific impacts as follows. Mutation of the LAZY1 gene, LjLAZY1, defected the gravitropic response of hypocotyl without impacting the main stem's branch angle. In contrast, the overexpression of the NGR gene, LjLAZY3, substantially modulated the shoot's gravitropism, leading to narrower lateral branch angles. Additionally, it enhanced the shoots' gravitropic response. The overexpression of another NGR gene, LjLAZY4, specifically reduced the main stem's branch angle and decreased plant stature without affecting the shoot gravitropic response. The phenotype of IGT-LIKE gene LjLAZY2 overexpression is identical to that of LjLAZY4. While overexpression of the IGT-LIKE gene LjLAZY5 did not induce any observable changes in branch angle, plant height, or gravitropic response. Furthermore, the LjLAZYs were selectively interacted with different BRXL and RLD proteins, which should the important factor to determine their different functions in controlling organ architecture in L. japonicus. Our results deepen understanding of the LjLAZY family and its potential for plant architecture improvement in L. japonicus.

Members of the MT-A70 family are key catalytic proteins involved in m⁶A methylation modifications in plants. They play diverse roles at the posttranscriptional level by regulating RNA secondary structure, selective splicing, stability, and translational efficiency, which collectively affect plant growth, development, and stress responses. In this study, we explored the function of the gene SlMTC, a Class C member of the MT-A70 family, in tomatoes by using CRISPR/Cas9 technology. Compared with the wild-type (WT), the CR-slmtc mutants exhibited decreased seed size and slower growth rates during the seedling stage, along with weaker salt tolerance and significant downregulation of stress-related genes, such as PR1, PR5, and P5CS. The qRT-PCR results revealed that the expression levels of genes involved in auxin biosynthesis (FZY1, FZY3, and FZY4) and polar transport (PIN1, PIN4, and PIN8) were lower in CR-slmtc plants than in the WT plants. In addition, yeast two-hybrid assays showed that SlMTC could interact with SlMTA, a Class A member of the MT-A70 family, providing insights into the potential mode of action of SlMTC in tomatoes. Overall, our findings indicate the critical role of SlMTC in plant growth and development as well as in response to salt stress.

The initiation of transition to flowering is carefully managed by endogenous and environmental cues, which is critical for flowering plant reproductive success. Here, we found that wheat RING-type E3 ligase TaFRFP was highly expressed from the double ridge to degeneration stage (WS2.5-WS9). TaFRFP is localized in the nucleus and has E3 ligase activity in vitro. TaFRFP overexpression in Arabidopsis resulted in an early flowering phenotype, but to a lesser extent, under short-day conditions. Under the SA-treated condition, overexpression of TaFRFP shows higher root growth and has more accumulation of SA contents. A proteomic comparison revealed that the amount of FRL4A protein, a FRIGIDA LIKE 4 A, was considerably lower in SA-treated TaFRFP seedlings compared to normal condition. We further found that TaFRFP directly interacts with FRL4A in the nucleus and recruits it to the FLC locus in Arabidopsis. Moreover, an ubiquitination assay showed that TaFRPF physically interact and ubiquitinates TaFRL as a substrate. Our findings support the concept that the TaFRFP E3 ligase works as a positive regulator, and that the ubiquitination of its substrate proteins plays a significant role in controlling flowering time via an SA-dependent pathway.