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

2022 ◽  
Vol 23 (2) ◽  
pp. 702
Author(s):  
Shuya Tan ◽  
Jie Cao ◽  
Xinli Xia ◽  
Zhonghai Li

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.

Author(s):  
Isabel Manrique-Gil ◽  
Inmaculada Sánchez-Vicente ◽  
Isabel Torres-Quezada ◽  
Oscar Lorenzo

Abstract Plants are aerobic organisms that have evolved to maintain specific requirements for oxygen (O2), leading to a correct respiratory energy supply during growth and development. There are certain plant developmental cues and biotic or abiotic stress responses where O2 is scarce. This O2 deprivation known as hypoxia may occur in hypoxic niches of plant-specific tissues and during adverse environmental cues such as pathogen attack and flooding. In general, plants respond to hypoxia through a complex reprogramming of their molecular activities with the aim of reducing the impact of stress on their physiological and cellular homeostasis. This review focuses on the fine-tuned regulation of hypoxia triggered by a network of gaseous compounds that includes O2, ethylene, and nitric oxide. In view of recent scientific advances, we summarize the molecular mechanisms mediated by phytoglobins and by the N-degron proteolytic pathway, focusing on embryogenesis, seed imbibition, and germination, and also specific structures, most notably root apical and shoot apical meristems. In addition, those biotic and abiotic stresses that comprise hypoxia are also highlighted.


2020 ◽  
Vol 21 (4) ◽  
pp. 1397 ◽  
Author(s):  
Purushothaman Natarajan ◽  
Tolulope Abodunrin Akinmoju ◽  
Padma Nimmakayala ◽  
Carlos Lopez-Ortiz ◽  
Marleny Garcia-Lozano ◽  
...  

Habanero peppers constantly face biotic and abiotic stresses such as pathogen/pest infections, extreme temperature, drought and UV radiation. In addition, the fruit cutin lipid composition plays an important role in post-harvest water loss rates, which in turn causes shriveling and reduced fruit quality and storage. In this study, we integrated metabolome and transcriptome profiling pertaining to cutin in two habanero genotypes: PI 224448 and PI 257145. The fruits were selected by the waxy or glossy phenotype on their surfaces. Metabolomics analysis showed a significant variation in cutin composition, with about 6-fold higher cutin in PI 257145 than PI 224448. It also revealed that 10,16-dihydroxy hexadecanoic acid is the most abundant monomer in PI 257145. Transcriptomic analysis of high-cutin PI 257145 and low-cutin PI 224448 resulted in the identification of 2703 statistically significant differentially expressed genes, including 1693 genes upregulated and 1010 downregulated in high-cutin PI 257145. Genes and transcription factors such as GDSL lipase, glycerol-3 phosphate acyltransferase 6, long-chain acyltransferase 2, cytochrome P450 86A/77A, SHN1, ANL2 and HDG1 highly contributed to the high cutin content in PI 257145. We predicted a putative cutin biosynthetic pathway for habanero peppers based on deep transcriptome analysis. This is the first study of the transcriptome and metabolome pertaining to cutin in habanero peppers. These analyses improve our knowledge of the molecular mechanisms regulating the accumulation of cutin in habanero pepper fruits. These resources can be built on for developing cultivars with high cutin content that show resistance to biotic and abiotic stresses with superior postharvest appearance.


2020 ◽  
Author(s):  
Chong Yang ◽  
Juanjuan Li ◽  
Faisal Islam ◽  
Luyang Hu ◽  
Jiansu Wang ◽  
...  

Abstract Background: WRKY transcription factors play important roles in various physiological processes and stress responses in flowering plants. However, the information about WRKY genes in Helianthus annuus L. (common sunflower) is limited. Results: Ninety WRKY (HaWRKY) genes were identified and renamed according to their locations on chromosomes. Further phylogenetic analyses classified them into four main groups including a species-specific WKKY group and HaWRKY genes within same group or subgroup generally showed similar exon-intron structures and motif compositions. The tandem and segmental duplication possibly contributed to the diversity and expansion of HaWRKY gene families. Synteny analyses of sunflower WRKY genes provided deep insight to the evolution of HaWRKY genes. Transcriptomic and qRT-PCR analyses of HaWRKY genes displayed distinct expression patterns in different plant tissues, as well as under various abiotic and biotic stresses. Conclusions: Ninety WRKY (HaWRKY) genes were identified from H. annuus L. and classified into four groups. Structures of HaWRKY proteins and their evolutionary characteristics were also investigated. The characterization of HaWRKY genes and their expression profiles under biotic and abiotic stresses in this study provide a foundation for further functional analyses of these genes. Therefore, these functional genes related to increasing the plant tolerance or improving the crop quality, could be applied for the crop improvement..


2019 ◽  
Vol 11 (2) ◽  
pp. 167-174
Author(s):  
Francisca I. OKUNGBOWA ◽  
Hakeem O. SHITTU ◽  
Henry O. OBIAZIKWOR

An endophyte is a microorganism, usually bacterium or fungus, which lives within the internal tissue of a host plant, causing no apparent harm. Some characteristics of an endophyte include ability to promote plant growth and to confer plant tolerance to biotic and abiotic stresses. Endophytic bacteria spread across many phyla including the Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria. Endophytic bacteria are recruited by hosts and they get attached to the surface and eventually find their way into the internal tissues where they spread to the intercellular spaces of host plants. These bacteria have been isolated and characterized from different plants. Currently, culture-independent methods such as sequencing of the 16S rRNA gene or metalogenomics are used for identification and characterization of endophytes. The mechanisms by which the endophyte-induced plant protection is brought about can be through direct and/or indirect methods. The direct strategy antagonizes phytopathogens by the production of chemical substances while the indirect mechanisms improve resistance of hosts to pathogens. Global gene expression studies on some common endophytic bacteria implicated these direct and indirect strategies of bacterial-induced protection. More research should be geared towards how the economic importance of endophytic bacteria could be utilized to enhance global food security.


2022 ◽  
Author(s):  
Yue Zhang ◽  
Shizhuo Lin ◽  
Jianping Wang ◽  
Meiling Tang ◽  
Jianfeng Huang ◽  
...  

Abstract As one of the most abundant ions in cells, potassium (K+) is closely related to plant growth and development and contributes to plant tolerance to various abiotic stresses. However molecular mechanisms towards K+ uptake and transport are unclear in tropic fruit trees. In this study, 18 KT/HAK/KUP family genes (MiHAKs) were isolated and characterized in mango. Results showed that MiHAKs were unevenly expressed in distinct tissues and were differentially responded to K+ depletion, PEG, and NaCl stresses in roots, in which K+ depletion and PEG treatment significantly enhanced while NaCl treatment mainly reduced responsive MiHAK genes. In particular, MiHAK14 was the most abundant KT/HAK/KUP family gene in mango, especially in roots. Functional complementation in TK2420 mutant revealed that MiHAK14 could uptake external K+. Moreover, overexpression of MiHAK14 in Arabidopsis enhanced plant tolerance to K+ depletion and NaCl stresses with strengthened K+ nutritional status and ROS scavenging ability. This study provides molecular basis for further functional studies of KT/HAK/KUP transporters in tropic fruit trees, and favorably demonstrates the essentiality of K+ homeostasis in plant tolerance to abiotic stresses, including K+ deficiency and NaCl stress.


Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 635
Author(s):  
Paola I. Angulo-Bejarano ◽  
Jonathan Puente-Rivera ◽  
Rocío Cruz-Ortega

Worldwide, the effects of metal and metalloid toxicity are increasing, mainly due to anthropogenic causes. Soil contamination ranks among the most important factors, since it affects crop yield, and the metals/metalloids can enter the food chain and undergo biomagnification, having concomitant effects on human health and alterations to the environment. Plants have developed complex mechanisms to overcome these biotic and abiotic stresses during evolution. Metals and metalloids exert several effects on plants generated by elements such as Zn, Cu, Al, Pb, Cd, and As, among others. The main strategies involve hyperaccumulation, tolerance, exclusion, and chelation with organic molecules. Recent studies in the omics era have increased knowledge on the plant genome and transcriptome plasticity to defend against these stimuli. The aim of the present review is to summarize relevant findings on the mechanisms by which plants take up, accumulate, transport, tolerate, and respond to this metal/metalloid stress. We also address some of the potential applications of biotechnology to improve plant tolerance or increase accumulation.


Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1403
Author(s):  
Jie Lin ◽  
Daofeng Liu ◽  
Xia Wang ◽  
Sajjad Ahmed ◽  
Mingyang Li ◽  
...  

The NAC (NAM, ATAFs, CUC) family of transcription factors (TFs) play a pivotal role in regulating all processes of the growth and development of plants, as well as responses to biotic and abiotic stresses. Yet, the functions of NACs from non-model plant species remains largely uncharacterized. Here, we characterized the stress-responsive effects of a NAC gene isolated from wintersweet, an ornamental woody plant that blooms in winter when temperatures are low. CpNAC68 is clustered in the NAM subfamily. Subcellular localization and transcriptional activity assays demonstrated a nuclear protein that has transcription activator activities. qRT-PCR analyses revealed that CpNAC68 was ubiquitously expressed in old flowers and leaves. Additionally, the expression of CpNAC68 is induced by disparate abiotic stresses and hormone treatments, including drought, heat, cold, salinity, GA, JA, and SA. Ectopic overexpression of CpNAC68 in Arabidopsis thaliana enhanced the tolerance of transgenic plants to cold, heat, salinity, and osmotic stress, yet had no effect on growth and development. The survival rate and chlorophyll amounts following stress treatments were significantly higher than wild type Arabidopsis, and were accompanied by lower electrolyte leakage and malondialdehyde (MDA) amounts. In conclusion, our study demonstrates that CpNAC68 can be used as a tool to enhance plant tolerance to multiple stresses, suggesting a role in abiotic stress tolerance in wintersweet.


2021 ◽  
Vol 12 ◽  
Author(s):  
Tianyi Dou ◽  
Lee Sanchez ◽  
Sonia Irigoyen ◽  
Nicolas Goff ◽  
Prakash Niraula ◽  
...  

Biotic and abiotic stresses cause substantial changes in plant biochemistry. These changes are typically revealed by high-performance liquid chromatography (HPLC) and mass spectroscopy-coupled HPLC (HPLC-MS). This information can be used to determine underlying molecular mechanisms of biotic and abiotic stresses in plants. A growing body of evidence suggests that changes in plant biochemistry can be probed by Raman spectroscopy, an emerging analytical technique that is based on inelastic light scattering. Non-invasive and non-destructive detection and identification of these changes allow for the use of Raman spectroscopy for confirmatory diagnostics of plant biotic and abiotic stresses. In this study, we couple HPLC and HPLC-MS findings on biochemical changes caused by Candidatus Liberibacter spp. (Ca. L. asiaticus) in citrus trees to the spectroscopic signatures of plant leaves derived by Raman spectroscopy. Our results show that Ca. L. asiaticus cause an increase in hydroxycinnamates, the precursors of lignins, and flavones, as well as a decrease in the concentration of lutein that are detected by Raman spectroscopy. These findings suggest that Ca. L. asiaticus induce a strong plant defense response that aims to exterminate bacteria present in the plant phloem. This work also suggests that Raman spectroscopy can be used to resolve stress-induced changes in plant biochemistry on the molecular level.


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