Environmental and Experimental Botany最新文献

In plants, alcohol dehydrogenases (ADHs) are involved in stress response, organ development, fruit ripening, and metabolite synthesis. However, little is known regarding ADH-encoding genes (ADHs) in Cucurbita moschata which is usually used as a rootstock for cucumber, melon, watermelon, and other cucurbit crops to resist soil-borne diseases and abiotic stresses. We identified 11 CmoADHs in the C. moschata genome that were unevenly distributed across seven chromosomes. These genes were predicted to encode stable cytoplasmic acidic proteins, sharing a low degree of identity with each other. The genes exhibited different intron–exon structures. Analysis of cis-acting regulatory elements showed that CmoADHs contain environmental stress-, hormone response-, light response-, and development/tissue specificity-related elements in their promoters. Expression pattern analysis revealed that CmoADH2, CmoADH3, CmoADH4, CmoADH9, CmoADH10, and CmoADH11 had the highest expression levels in the roots, which were significantly higher than those in the other tested tissues. These six genes may play important roles in the growth and development of roots, and in related abiotic stress responses. CmoADH1, CmoADH5, CmoADH6, CmoADH7, CmoADH8 had the highest expression in the apical region and could be involved in the differentiation of newly formed tissues. To study the role of CmoADHs in abiotic stress, salt, drought, low temperature, and ethephon treatments were performed. Under drought conditions, CmoADHs showed different expression trends. The expression levels of CmoADH1, CmoADH2, CmoADH3, and CmoADH9 increased significantly and peaked after 1 h of drought treatment, indicating that these four genes are more sensitive to drought stress. Under salt treatment, all CmoADHs showed a significant increase or decrease in expression within 6 h, except for CmoADH5 and CmoADH10, which were insensitive to salt treatment. The expression of most of the CmoADHs was significantly downregulated by low-temperature treatment. Ethephon treatment significantly induced the expression of all the CmoADHs, except CmoADH2, to different degrees within 12 h. CmoADH9 was found to be involved in root growth and drought stress resistance. Identification of these ADH genes can provide useful resources for conferring stress resistance in other economically important crops.

The intensification of droughts due to climate change is a global concern, and many plant species face increasing water deficits. Understanding the role of phenotypic plasticity in plant adaptation to these changing conditions is crucial. This research focuses on Bromopsis erecta, a dominant perennial grass in European and Mediterranean grasslands, to predict its potential adaptation to climate change. We assessed plants from shallow and deep soils (i.e., with contrasting water reserves) of a Mediterranean rangeland in southern France, and tested the effect of six years of experimentally increased summer drought compared to the ambient conditions on plant traits, survival and abundance. In both field and common garden experiments, we measured water-related traits, including static traits under non-limiting water conditions, and dynamic traits, such as rates of trait variation during drought. Trait plasticity was determined as a reaction norm to increasing soil water stress and was tested against changes in B. erecta abundance over the past decade, including the study period. Trait plasticity was detected only for leaf dry matter content (LDMC), revealing that the resource strategy of B. erecta became more conservative over less than a decade with higher LDMC and leaf thickness according to the plant economic spectrum. No plasticity was found for osmotic potential or specific leaf area. The variability of other traits was ascribed to the possible lagging effect of previous water stress and was associated more with soil depth than with previous summer drought intensity. The abundance decline of B. erecta, which dropped from 20 % to around 5 % in shallow soils, was not associated with the plasticity of LDMC but was positively correlated with variations in leaf base membrane damage, meaning unexpectedly, that plants exposed to the most severe summer drought also had the most sensitive leaf base membranes, a possible sign of maladaptive trait plasticity in the population. This key trait response reveals boundaries to the adaptive capacity of this perennial grass to survive pluri-annual drought.

Late embryogenesis abundant (LEA) proteins play a crucial role in determining how plants respond to abiotic stress. Nonetheless, the comprehensive characterization and function of the LEA gene family in Ammopiptanthus nanus, an endangered evergreen shrub plant that survived in harsh desert environments, are largely unknown. Through a comprehensive genome-wide investigation, we successfully identified 45 AnLEA genes in A. nanus and divided them into eight groups. AnLEAs have typical LEA domains, and the promoter analysis shows that they contain various cis-regulatory elements related to stress resistance. The diverse expression patterns of AnLEAs under different abiotic stress treatments suggest that they play an important role in responding to stress. Overexpression of AnLEA30 in tobacco significantly enhanced abiotic stress tolerance by effectively stabilizing and protecting membranes, scavenging reactive oxide species (ROS), and improving photosynthesis, demonstrating the potential for application of AnLEA30 in plant improvement.

Exogenous selenium (Se) addition can dynamically regulate the establishment of microbial communities, induce the expression of specific microbial functional genes, and affect the homeostasis of the soil-plant microenvironment. In this study, we used metagenomic and metabolomic analyses to investigate Se-mediated homeostatic changes and functional responses in the rhizosphere soil of rice seedlings. Results show that compared with the Cd set, selenium (1 mg/kg) Se content in the Soil and rice plant increased by 88.5 % and 99.1 %, respectively. Soil-fluorescein diacetate (S-FDA) hydrolyze enzymatic activity increased by 42.9 %, Rice on Cd enrichment coefficient increased by 71.1 %, but the transfer coefficient by 21.6 %, making a lot of cadmium ion stranded in the root, easing the toxicity of cadmium to plant. Metagenomic analysis revealed that Se bioaugmentation altered the structure and composition of the rhizosphere microbial community and induced remodeling of the rice rhizosphere microbiome. Increase the heavy metal resistance genes (cznA czcD, czcP, dltC, and CREM), nutrient cycling functional genes (atoB tktB, acs, sdhA, accA, ppdK, NRT, narB, nifD, napA, pstS, GlpQ, spoT, phoR, sucC) and heavy metal transport protein family (P-ATPase, CDF, ABC, and MIT) expression. It significantly improved the health of the rhizosphere microenvironment and alleviated soil hardening and nutrient deficiency caused by heavy metals. At the same time, in metabonomics analysis, The upregulated Differentially expressed metabolites (DEMs) were mainly in the Biosynthesis of siderophore group nonribosomal peptides, Sulfur metabolism, Ubiquinone and other terpenoid-quinone Biosynthesis, Cysteine, and methionine metabolism in enrichment significantly. The mediated reshaping of rhizosphere microorganism groups indicates that there is ane an advantage in the nutrient cycle. Also, the secondary metabolism and antioxidant capacity have significantly strengthened the ed, and the large strain caused by the death of heavy metals is a result of poor Soil. In addition, the Cyclic adenosine monophosphate (CAMP) signaling pathway was activated among the remodeling microbiomes, and the receptor protein inducer was upregulated, which activated the population response among the rhizosphere microbiomes and resulted in the overexpression of specific functional genes of each microbiome. By enhancing the resistance to heavy metals and nutrient cycling ability of the rhizosphere microbiome, the mobility and bioavailability of Cd ions were significantly reduced, the rhizosphere soil microenvironment health was improved, and the adaptability of rice to Cd stress was improved. This study reveals the Se of rice rhizosphere Cd-resistant bacteria mediating mechanisms; research for precise regulation of plant rhizosphere microorganism groups opens new avenues of research and offers a new way for crop production safety.

Chromium phytotoxicity results in relevant alterations to plant physiology, gene expression, and genomic DNA methylation at a transgenerational level. Herein, transcriptional responses of durum wheat (Triticum turgidum L.) to chronic chromium exposure were explored in roots and leaves by RNA-seq approach. Plants grown all the time in a hydroponic system supplemented with 2.5 and 10 µM hexavalent chromium were compared to unstressful control plants, assessing biomass and seed yield analyses after senescence. Then, transcriptomic analysis was performed with these plants kept under 10 µM chromium 50 days after the onset of exposure. The chromium concentrations used were considered the lowest dose sufficient to alter gene expression without impeding plant development, while the sampling time reflected the effects in the pre-harvest phase and long-lasting defense mechanisms. Root and leaf samples from plants kept under 10 µM chromium stress and from unstressful control plants were analyzed, generating 12 RNA-seq libraries. In total, 965 and 810 transcripts were found to be differentially expressed, respectively, in roots and leaves in response to 10 µM chromium stress. In roots, transcriptional changes were noted in the primary and secondary metabolism, redox homeostasis, protein modification, solute transport, nutrient uptake, and external stimuli responses. Meanwhile, the transcriptional changes in leaves were primarily found in the secondary metabolism, hormone-related pathways, chromatin modifications, cell division, protein modification and homeostasis, solute transport, and nutrient uptake. In particular, the metal uptake and translocation pathways were studied with greater emphasis to identify key proteins involved in chromium transport and compartmentalization. Furthermore, several genes involved in the biosynthesis of malate-derived organic acids, trace metal transport/detoxification/chelation, and vacuolar compartmentalization were linked to primary defense responses, and some of them were also associated with two putative gene clusters. Therefore, these genes and gene clusters are suggested as valuable biotechnological targets for future proof-of-concept studies aimed at genetic engineering of durum wheat to improve plant tolerance to chromium exposure.

The FtsH (Filamentous temperature sensitive H) proteases, known for their crucial roles in protein quality control and maintaining the integrity of photosynthetic machinery, have emerged as key regulators of stress responses in plants. Our previous study revealed the overexpression of MsFtsH8, an FtsH gene from alfalfa (Medicago sativa L.), confers salt stress tolerance to the plant. By comparing the proteomic profiles of MsFtsH8-overexpressing alfalfa and wild type under salt stress conditions, we elucidate the molecular pathways underlying MsFtsH8-mediated salt stress resilience. We identified 730 differentially expressed proteins (DEPs) in MsFtsH8-overexpressing alfalfa under salt stress, compared to 498 DEPs in wild type alfalfa under the same growth condition. Our results reveal significant alterations in the expression of proteins involved in the photosynthetic system, consistent with the chloroplast subcellular localization of MsFtsH8. Specifically, MsFtsH8 overexpression stabilizes key components of Photosystem II (PSII) and enhances electron transport processes, leading to increased photosynthetic efficiency and oxidative photodamage repair capacity under salt stress. Moreover, MsFtsH8-overexpressing alfalfa exhibits elevated levels of antioxidative enzymes, further mitigating oxidative damage induced by high salinity. These findings deepen our understanding of the regulatory role of MsFtsH8 in salt stress response and highlight its potential for improving crop resilience under adverse environmental conditions.