Antisense-mediated S-adenosyl-L-methionine decarboxylase silencing affects heat stress responses of tobacco plants

2020 ◽  
Vol 47 (7) ◽  
pp. 651
Author(s):  
Ifigeneia Mellidou ◽  
Katerina Karamanoli ◽  
Helen-Isis A. Constantinidou ◽  
Kalliopi A. Roubelakis-Angelakis

Understanding the molecular mode(s) of plant tolerance to heat stress (HS) is crucial since HS is a potential threat to sustainable agriculture and global crop production. Polyamines (PAs) seem to exert multifaceted effects in plant growth and development and responses to abiotic and biotic stresses, presumably via their homeostasis, chemical interactions and contribution to hydrogen peroxide (H2O2) cellular ‘signatures’. Downregulation of the apoplastic POLYAMINE OXIDASE (PAO) gene improved thermotolerance in tobacco (Nicotiana tabacum L.) transgenics. However, in the present work we show that transgenic tobacco plants with antisense-mediated S-ADENOSYL-L-METHIONINE DECARBOXYLASE silencing (AS-NtSAMDC) exhibited enhanced sensitivity and delayed responses to HS which was accompanied by profound injury upon HS removal (recovery), as assessed by phenological, physiological and biochemical characteristics. In particular, the AS-NtSAMDC transgenics exhibited significantly reduced rate of photosynthesis, as well as enzymatic and non-enzymatic antioxidants. These transgenics suffered irreversible damage, which significantly reduced their growth potential upon return to normal conditions. These data reinforce the contribution of increased PA homeostasis to tolerance, and can move forward our understanding on the PA-mediated mechanism(s) conferring tolerance to HS that might be targeted via traditional or biotechnological breeding for developing HS tolerant plants.

Agronomy ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 788 ◽  
Author(s):  
Youngdae Yoon ◽  
Deok Hyun Seo ◽  
Hoyoon Shin ◽  
Hui Jin Kim ◽  
Chul Min Kim ◽  
...  

Abiotic stresses, such as drought, high temperature, and salinity, affect plant growth and productivity. Furthermore, global climate change may increase the frequency and severity of abiotic stresses, suggesting that development of varieties with improved stress tolerance is critical for future sustainable crop production. Improving stress tolerance requires a detailed understanding of the hormone signaling and transcriptional pathways involved in stress responses. Abscisic acid (ABA) and jasmonic acid (JA) are key stress-response hormones in plants, and some stress-responsive transcription factors such as ABFs and MYCs function as direct components of ABA and JA signaling, playing a pivotal role in plant tolerance to abiotic stress. In addition, extensive studies have identified other stress-responsive transcription factors belonging to the NAC, AP2/ERF, MYB, and WRKY families that mediate plant response and tolerance to abiotic stress. These suggest that transcriptional regulation of stress-responsive genes is an essential step to determine the mechanisms underlying plant stress responses and tolerance to abiotic stress, and that these transcription factors may be important targets for development of crops with enhanced abiotic stress tolerance. In this review, we briefly describe the mechanisms underlying plant abiotic stress responses, focusing on ABA and JA metabolism and signaling pathways. We then summarize the diverse array of transcription factors involved in plant responses to abiotic stress, while noting their potential applications for improvement of stress tolerance.


2015 ◽  
Vol 140 (3) ◽  
pp. 257-264 ◽  
Author(s):  
Zipeng Tian ◽  
Bingru Huang ◽  
Faith C. Belanger

Strong creeping red fescue (Festuca rubra ssp. rubra) is an important cool season turfgrass species. Cultivars are often infected with the fungal endophyte Epichloë festucae. Endophyte infection is known to confer insect and disease resistance to the plants. The effect of endophyte infection on drought or heat stress tolerance of strong creeping red fescue is not yet established. The objectives of this controlled-environment study were to determine if endophyte infection had any effect on physiological parameters associated with plant tolerance to drought or heat stress or the combination of the two stresses. In this study, endophyte status had no effect on turf quality (TQ), relative water content (RWC), photochemical efficiency, chlorophyll content, electrolyte leakage (EL), or malondialdehyde (MDA) content of the plants under any of the stress treatments. Our results suggested that E. festucae infection had no physiological effects on improving drought, heat or the combined stress tolerance in strong creeping red fescue.


2020 ◽  
Vol 71 (13) ◽  
pp. 3780-3802 ◽  
Author(s):  
Michela Janni ◽  
Mariolina Gullì ◽  
Elena Maestri ◽  
Marta Marmiroli ◽  
Babu Valliyodan ◽  
...  

Abstract To ensure the food security of future generations and to address the challenge of the ‘no hunger zone’ proposed by the FAO (Food and Agriculture Organization), crop production must be doubled by 2050, but environmental stresses are counteracting this goal. Heat stress in particular is affecting agricultural crops more frequently and more severely. Since the discovery of the physiological, molecular, and genetic bases of heat stress responses, cultivated plants have become the subject of intense research on how they may avoid or tolerate heat stress by either using natural genetic variation or creating new variation with DNA technologies, mutational breeding, or genome editing. This review reports current understanding of the genetic and molecular bases of heat stress in crops together with recent approaches to creating heat-tolerant varieties. Research is close to a breakthrough of global relevance, breeding plants fitter to face the biggest challenge of our time.


Author(s):  
Hasrat Arjjumend ◽  
Konstantia Koutouki ◽  
Olga Donets

The use of unsustainable levels of chemical fertilizers and plant protection chemicals has resulted in a steady decline in soil and crop productivity the world over. Soil biology has undergone irreversible damage, coupled with a high concentration of toxic chemical residues in plant tissues and human bodies. Agricultural practices must evolve to sustainably meet the growing global demand for food without irreversibly damaging soil. Microbial biocontrol agents have tremendous potential to bring sustainability to agriculture in a way that is safe for the environment. Biopesticides do not kill non-target insects, and biosafety is ensured because biopesticides act as antidotes and do not lead to chemical contamination in the soil. This article is part of a larger study conducted in Ukraine by researchers at the Université de Montréal with the support of Mitacs and Earth Alive Clean Technologies. The responses of farmers who use biofertilizers (“user farmers”) and those who do not (“non-user farmers”), along with the responses of manufacturers or suppliers of biofertilizers, and research and development (R&D) scientists are captured to demonstrate the advantages of applying microbial biopesticides to field crops. Participants reported a 15-30% increase in yields and crop production after the application of biopesticides. With the use of biopesticides, farmers cultivated better quality fruits, grains, and tubers with a longer shelf life. Moreover, while the risk of crop loss remains high (60-70%) with chemically grown crops, this risk is reduced to 33% on average if crops are grown using biopesticides. The findings indicate that a large proportion of farmers would prefer to use biopesticides if they are effective and high quality products. In this context, the quality and effectiveness of products is therefore very important. Despite their benefits to soil, human health, and ecosystems, biopesticides face significant challenges and competition vis-à-vis synthetic pesticides for a variety of reasons. Therefore, the development of biopesticides must overcome the problems of poor quality products, short shelf life, delayed action, high market costs, and legal/registration issues.


Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 419
Author(s):  
Jordi Sardans ◽  
Josep Peñuelas

Potassium, mostly as a cation (K+), together with calcium (Ca2+) are the most abundant inorganic chemicals in plant cellular media, but they are rarely discussed. K+ is not a component of molecular or macromolecular plant structures, thus it is more difficult to link it to concrete metabolic pathways than nitrogen or phosphorus. Over the last two decades, many studies have reported on the role of K+ in several physiological functions, including controlling cellular growth and wood formation, xylem–phloem water content and movement, nutrient and metabolite transport, and stress responses. In this paper, we present an overview of contemporary findings associating K+ with various plant functions, emphasizing plant-mediated responses to environmental abiotic and biotic shifts and stresses by controlling transmembrane potentials and water, nutrient, and metabolite transport. These essential roles of K+ account for its high concentrations in the most active plant organs, such as leaves, and are consistent with the increasing number of ecological and agricultural studies that report K+ as a key element in the function and structure of terrestrial ecosystems, crop production, and global food security. We synthesized these roles from an integrated perspective, considering the metabolic and physiological functions of individual plants and their complex roles in terrestrial ecosystem functions and food security within the current context of ongoing global change. Thus, we provide a bridge between studies of K+ at the plant and ecological levels to ultimately claim that K+ should be considered at least at a level similar to N and P in terrestrial ecological studies.


2021 ◽  
Vol 13 (12) ◽  
pp. 2349
Author(s):  
Jingchun Ji ◽  
Jianli Liu ◽  
Jingjing Chen ◽  
Yujie Niu ◽  
Kefan Xuan ◽  
...  

Topdressing accounts for approximately 40% of the total nitrogen (N) application of winter wheat on the Huang-Huai-Hai Plain in China. However, N use efficiency of topdressing is low due to the inadaptable topdressing method used by local farmers. To improve the N use efficiency of winter wheat, an optimization method for topdressing (THP) is proposed that uses unmanned aerial vehicle (UAV)-based remote sensing to accurately acquire the growth status and an improved model for growth potential estimation and optimization of N fertilizer amount for topdressing (NFT). The method was validated and compared with three other methods by a field experiment: the conventional local farmer’s method (TLF), a nitrogen fertilization optimization algorithm (NFOA) proposed by Raun and Lukina (TRL) and a simplification introduced by Li and Zhang (TLZ). It shows that when insufficient basal fertilizer was provided, the proposed method provided as much NFT as the TLF method, i.e., 25.05% or 11.88% more than the TRL and TLZ methods and increased the yields by 4.62% or 2.27%, respectively; and when sufficient basal fertilizer was provided, the THP method followed the TRL and TLZ methods to reduce NFT but maintained as much yield as the TLF method with a decrease of NFT by 4.20%. The results prove that THP could enhance crop production under insufficient N preceding conditions by prescribing more fertilizer and increase nitrogen use efficiency (NUE) by lowering the fertilizer amount when enough basal fertilizer is provided.


2021 ◽  
Author(s):  
Yuanyuan Wang ◽  
S.M. Impa ◽  
Ramanjulu Sunkar ◽  
S.V. Krishna Jagadish
Keyword(s):  

2020 ◽  
Author(s):  
Albert Maibam ◽  
Sunil Nigombam ◽  
Harinder Vishwakarma ◽  
Showkat Ahmad Lone ◽  
Kishor Gaikwad ◽  
...  

Abstract Background Pennisetum glaucum (L.) R. Br. is mainly grown in arid and semi-arid regions. Being naturally tolerant to various adverse condtitions, it is a good biological resource for deciphering the molecular basis of abiotic stresses such as heat stress in plants but limited studies have been carried out till date to this effect. Here, we performed RNA-sequencing from the leaf of two contrasting genotypes of pearl millet (841-B and PPMI-69) subjected to heat stress (42 °C for 6 h). Results Over 274 million high quality reads with an average length of 150 nt were generated. Assembly was carried out using trinity, obtaining 47,310 unigenes having an average length of 1254 nucleotides, N50 length of 1853 nucleotides and GC content of 53.11%. Blastx resulted in annotation of 35,628 unigenes and functional classification showed 15,950 unigenes designated to 51 Gene Ontology terms, 13,786 unigenes allocated to 23 Clusters of Orthologous Groups and 4,255 unigenes distributed into 132 functional KEGG pathways. 12,976 simple sequence repeats were identified from 10,294 unigenes for the development of functional markers. A total of 3,05,759 SNPs were observed in the transcriptome data. Out of 2,301 differentially expressed genes, 10 potential candidates genes were selected based on log2 fold change and adjusted p-value parameters for their differential gene expression by qRT-PCR. Conclusions The dynamic expression changes in two genotypes of P. glaucum reflect transcriptome regulation of signaling pathways in heat stress response. In order to develop genetic markers, 12,976 simple sequence repeats (SSRs) were identified. The sequencing data generated in this study shall serve as an important resource for further research in the area of crop biotechnology.


2020 ◽  
Author(s):  
Iman Haqiqi ◽  
Danielle S. Grogan ◽  
Thomas W. Hertel ◽  
Wolfram Schlenker

Abstract. Agricultural production and food prices are affected by hydroclimatic extremes. There has been a large literature measuring the impacts of individual extreme events (heat stress or water stress) on agricultural and human systems. Yet, we lack a comprehensive understanding of the significance and the magnitude of the impacts of compound extremes. Here, we combine a high-resolution weather product with fine-scale outputs of a hydrological model to construct functional indicators of compound hydroclimatic extremes for agriculture. Then, we measure the impacts of individual and compound extremes on crop yields focusing on the United States during the 1981–2015 period. Supported by statistical evidence, we confirm that wet heat is more damaging than dry heat for crops. We show that the average damage from heat stress has been up to four times more severe when combined with water stress; and the value of water experiences a four-fold increase on hot days. In a robust framework with only a few parameters of compound extremes, this paper also improves our understanding of the conditional marginal value (or damage) of water in crop production. This value is critically important for irrigation water demand and farmer decision-making – particularly in the context of supplemental irrigation and sub-surface drainage.


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