Invasive Species in a Changing World

Chickpea is one of the world's largest cultivated food legume and is an excellent source of high‐quality protein to the human diet. Plant growth and development are controlled by programmed expression of a suite of genes at the given time, stage and tissue. Understanding how the underlying genome sequence translates into specific plant phenotypes at key developmental stages, information on gene expression patterns is crucial. Here we present a comprehensive Cicer arietinum Gene Expression Atlas (CaGEA) across the plant developmental stages and organs covering the entire life cycle of chickpea. One of the widely used drought tolerant cultivar, ICC 4958 has been used to generate RNA‐Seq data from 27 samples at five major developmental stages of the plant. A total of 816 million raw reads were generated and of these, 794 million filtered reads after QC were subjected to downstream analysis. A total of 15,947 unique number of differentially expressed genes across different pairwise tissue combinations were identified. Significant differences in gene expression patterns contributing in the process of flowering, nodulation, seed and root development were inferred in this study. Furthermore, differentially expressed candidate genes from “QTL‐hotspot” region associated with drought stress response in chickpea were validated.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/pce.13210

The RNA-Seq-based high resolution gene expression atlas of chickpea (Cicer arietinum L.) reveals dynamic spatio-temporal changes associated with growth and development.

Sulfur (S) is a macronutrient for the plant, which has an immense role in basic plant processes and regulation of several metabolic pathways. It has also a major role in providing protection against adverse conditions. Sulfur-containing amino acids and metabolites maintain plant cell mechanisms to improve stress tolerance. It interacts with several biomolecules such as phytohormones, polyamines, nitric oxide (NO), and even with other plant nutrients, which can produce some derivatives those are essential for abiotic stress tolerance. Different S derivatives stimulate signaling cascades, for the upregulation of different cellular messengers such as abscisic acid, Ca2+, and NO. Sulfur is also known to interact with some essential plant nutrients by influencing their uptake and transport, hence, confers nutrient homeostasis efficiencies. This review focuses on how S is interacted with several signaling molecules like NO, glutathiones, phytohormones, hydrogen sulfide, polyamines, etc. This is a concise summary aimed at guiding the researchers to study S-related plant processes in the light of abiotic stress tolerance.

https://www.tandfonline.com/doi/pdf/10.1080/15592324.2018.1477905

Interaction of sulfur with phytohormones and signaling molecules in conferring abiotic stress tolerance to plants.

Plants are frequently exposed to different stressful factors, both of biotic or abiotic nature, which limit their growth and productivity. To survive under stress conditions, plants must activate stress-specific signalling pathways, which finally lead to morphological, physiological, and biochemical changes that allow to adapt to the adverse environment. Cellular redox homeostasis, determined by a complex interplay between pathways that produce and scavenge reactive oxygen species (ROS), plays a key role in the adaptive response. Each deviation in the cellular redox state, due to an imbalance of ROS production and/or scavenging, is indicative of environmental disturbance and works as a signal. Under stress conditions, different ROS are produced in many cell compartments. Plants have very proficient, versatile and flexible antioxidant machinery, which comprises enzymes and metabolites with distinct biochemical properties and distinct sub-cellular localization. The antioxidant systems play a key role in the control of redox homeostasis, determining either the extent or the specificity of ROS signals and the downstream redox-dependent responses. Redox signalling is responsive to a number of environmental cues, and the complex and dynamic pathways of redox regulation occur in different cell compartments. The redox-dependent modification of sensitive signalling proteins is proposed as a key mode of redox signal transmission. Each redox-dependent interaction is opportunely regulated by a restricted environment, whose change transfers the complex system of information and influences the plant response to external changes.

Redox State as a Central Regulator of Plant-Cell Stress Responses

Potential roles of melatonin and sulfur in alleviation of lanthanum toxicity in tomato seedlings.

Plants assimilate inorganic sulfur and metabolize it further to organic sulfur compounds essential for plant growth, development, and stress mitigation. Animals including humans in turn depend on plants and microorganisms providing these essential compounds, such as the amino acid methionine, which they cannot synthesize. Furthermore, a number of sulfur-containing metabolites provide the characteristic tastes and smells of our food, and many of them are known to have health promoting and protective properties. Thus, adequate supply of sulfur can be a critical factor affecting crop yield and production of beneficial phytochemicals. However, because of the reduction in anthropogenic emission of sulfur dioxide to the atmosphere, particularly from developed countries, sulfur deficiency has become a problem for agriculture and in many areas sulfur fertilization is required to ensure yield, quality, and health of crops. Such an impact of sulfur has triggered research into mechanisms of sulfur metabolism in plants and its regulation. Indeed great progress has been made over the last decades as summarized in several recent reviews (Takahashi et al., 2011; Sauter et al., 2013; Calderwood and Kopriva, 2014). Starting with identification of genes encoding components of sulfur metabolism, research in molecular biology and molecular genetics has brought us toward finding regulators and signals controlling the pathway (Maruyama-Nakashita et al., 2006; Gigolashvili et al., 2007; Hirai et al., 2007), and describing natural variation in diverse sulfur related traits (Kliebenstein et al., 2001; Loudet et al., 2007; Chao et al., 2014). In addition, questions related to regulation of sulfur metabolism have been on the forefront of systems biology (Maruyama-Nakashita et al., 2003; Hirai et al., 2005; Nikiforova et al., 2005) and quantitative genetics (Loudet et al., 2007). This research topic organized in Frontiers in Plant Science has been an opportunity to present our current understanding and research progress focused on a number of interesting aspects in plant sulfur metabolism. We aimed to cover broad research topics in sulfur nutrition and metabolism by compiling diverse types of articles: original research reports to exemplify new information on questions the sulfur research community is addressing, focused reviews to provide detailed updates to specific topics, and perspectives to review a progress but also to address the questions for the next decade(s) of research. This concept found indeed a great support in the sulfur research community with 34 articles contributed by scholars representing wide disciplinary areas.

/pdf/editorial-frontiers-of-sulfur-metabolism-in-plant-growth-1hp6juy5r9.pdf

Editorial: Frontiers of Sulfur Metabolism in Plant Growth, Development, and Stress Response.

Two common bean (Phaseolus vulgaris L.) mutants, sodPv 1 and sodPv 2, exhibiting foliar superoxide dismutase (SOD) activity of only 25% and 40% of their mother control (MC) cv. VL 63 were isolated in EMS-mutagenized (0.15%, 8 h) M2 progeny. Native-PAGE analysis revealed occurrence of Mn SOD, Fe SOD, Cu/Zn SOD I and Cu/Zn SOD II isozymes in MC, while Fe SOD, and Mn SOD were not formed in sodPv 1 and sodPv 2 leaves, respectively. In-gel activity of individual isozymes differed significantly among the parents. SOD deficiency is inherited as recessive mutations, controlled by two different nonallelic loci. Gene expressions using qRT PCR confirmed higher expressions of Cu/Zn SOD transcripts in both mutants and the absence of Fe SOD in sodPv 1 and Mn SOD in sodPv 2. In 50 μM arsenic, Cu/Zn SODs genes were further upregulated but other isoforms downregulated in the two mutants, maintaining SOD activity in its control level. In an F2 double mutants of sodPv 1 × sodPv 2, no Fe SOD, and Mn SOD expressions were detectable, while both Cu/Zn SODs are down-regulated and arsenic-induced leaf necrosis appeared. In contrast to both mutants, ROS-imaging study revealed overaccumulation of both superoxides and H2O2 in leaves of double mutant.

/pdf/superoxide-dismutase-deficient-mutants-in-common-beans-2vkaptoerw.pdf

Superoxide-Dismutase Deficient Mutants in Common Beans (Phaseolus vulgaris L.): Genetic Control, Differential Expressions of Isozymes, and Sensitivity to Arsenic

Inheritance of growth habit and leaf-shape in mungbean [Vigna radiata (L.) Wilczek.]

Two catalase (CAT)-deficient mutants namely, catLc1 and catLc2 were isolated in EMS-induced (0.15% and 0.5%, 6 h) M2 population of lentil (Lens culinaris Medik.) var. VL 125. Leaf and root CAT activity was only about 22.53% and 9.16%, respectively, in catLc1, and was nearly 11.22% and 30.84% of mother variety in catLc2. Sharp differences were observed between the two mutants for morpho-physiological, antioxidant status and cytogenetic parameters. Compared to mother variety, root growth was affected in catLc1, while shoot growth was markedly reduced in catLc2 mutant. Significantly low redox status of ascorbate and glutathione under CAT-deficiency presumably crippled the H2O2scavenging capacity, resulting in abnormal accumulation of H2O2 and concomitantly, high rate of membrane lipid peroxidation and electrolyte leakage as the marks of oxidative stress in the two mutants with more severe effect in roots of catLc1 and leaves of catLc2. At controlled pot experiment under a range of irradiance (100-400 μmol m -2 s -1 ), CATdeficiency coupled with membrane damage increased in catLc2 plants, while catLc1 mutant was largely unaffected. Under CAT-deficiency, mitotic disruptions were severe in catLc1 roots while meiotic anomalies were very high in catLc2. CATdeficiency in lentil originated as recessive mutations by the action of two different non-allelic loci.

Tulika Talukdar

Papers

Editorial: Frontiers of Sulfur Metabolism in Plant Growth, Development, and Stress Response.

Superoxide-Dismutase Deficient Mutants in Common Beans (Phaseolus vulgaris L.): Genetic Control, Differential Expressions of Isozymes, and Sensitivity to Arsenic

Inheritance of growth habit and leaf-shape in mungbean [Vigna radiata (L.) Wilczek.]

Catalase-deficient mutants in lentil (Lens culinaris Medik.): perturbations in morpho-physiology, antioxidant redox and cytogenetic parameters.

Frontiers of Sulfur Metabolism in Plant Growth, Development, and Stress Response