The SPL transcription factor genes are potential targets for epigenetic regulation in response to drought stress in chickpea (C. arietinum L.).

BACKGROUND: Crop improvement for tolerance to various biotic and abiotic stress factors necessitates understanding the key gene regulatory mechanisms. One such mechanism of gene regulation involves changes in cytosine methylation at the gene body and flanking regulatory sequences. The present study was undertaken to identify genes which might be potential targets of drought-induced DNA methylation in chickpea. METHODS AND RESULTS: Two chickpea genotypes, which contrast for drought tolerance, were subjected to drought stress conditions and their differential response was studied by analysing different morpho-physiological traits. Utilizing the in-house, high throughput sequencing data, the SQUAMOSA promoter-binding (SBP) protein-like (SPL) transcription factor genes were identified to be differentially methylated and expressed amongst the two genotypes, in response to drought stress. The methylation status of one of these genes was examined and validated through bisulfite PCR (BS-PCR). The identified genes could be possible homologs to known epialleles and can therefore serve as potential epialleles which can be utilized for crop improvement in chickpea. CONCLUSION: The SPL TF genes are potential targets of epigenetic regulation in response to drought stress in chickpea. Since these are TFs, they might play important roles in controlling the expression of other genes, thus contributing to differential drought response of the two genotypes.

Characterization of a unique Sikkimese yak population of India: a multivariate approach.

Native Sikkimese yak in Sikkim state of India is a pastoral treasure being raised through centuries-old transhumance practices and has evolved in response to natural and man-made selection. Currently, the population of Sikkimese yak is at risk with about five thousand total headcounts. Characterization is essential for taking appropriate decisions for conservation of any endangered population. In an attempt to phenotypically characterize the Sikkimese yaks, this study recorded phenotypic morphometric traits information, viz., body length (LG), height at withers (HT), heart girth (HG), paunch girth (PG), horn length (HL), horn circumference (HC), distance between horns (DbH), ear length (EL), face length (FL), face width (FW), and tail length with switch (TL), on 2154 yaks of both sexes. Multiple correlation estimation highlighted that HG and PG, DbH and FW, and EL and FW were highly correlated. Using principal component analysis, LG, HT, HG, PG, and HL were found to be the most important traits for phenotypic characterization of Sikkimese yak animals. Discriminant analysis based on different locations of Sikkim hinted at the existence of two separate clusters, however, broadly, phenotypic uniformity could be observed. Subsequent genetic characterization can offer greater insights and can pave the way for future breed registration and conservation of the population.

Bilateral variation in the branching pattern of the subclavian artery: an unusual finding with clinical implications.

The subclavian artery is a significant branch of the aortic arch. We present a rare case of a bilateral variation in the branching pattern of the subclavian artery, observed in an adult male cadaver aged 70 years. On both the sides of the neck, all the branches of the subclavian artery took their origin from its first part. There was a rare occurrence of a cervicodorsoscapular trunk, which gave rise to superficial cervical, suprascapular, and dorsal scapular arteries. The same branching pattern was observed on the left side of the neck, with the presence of another cervicodorsoscapular trunk. Thyrocervical trunk and transverse cervical artery were both absent from the cervical region bilaterally. The inferior thyroid artery was a direct branch from the subclavian artery. Knowledge regarding variations of the subclavian artery is very important as lateral cervical region arteries are important for flap harvesting in plastic and reconstruction surgery. Preoperative radiologic evaluation of pedicles might help in choosing the optimal flap design, prevent ischemic complications, and help to improve overall treatment outcomes.

A artéria subclávia é um ramo significativo do arco da aorta. Apresentamos um caso raro de variação bilateral do padrão de ramificação da artéria subclávia, observada em um cadáver adulto do sexo masculino de 70 anos. Em ambos os lados do pescoço, todos os ramos da artéria subclávia originavam-se de sua primeira parte. Houve rara ocorrência de tronco escapular cervical dorsal, que deu origem às artérias cervical superficial, supraescapular e escapular dorsal. O mesmo padrão de ramificação foi observado no lado esquerdo do pescoço, com a presença de tronco escapular cervical dorsal. O tronco tireocervical e a artéria cervical transversa estavam ausentes em ambas as regiões cervicais direita e esquerda. A artéria tireóidea inferior consistia em um ramo direto da artéria subclávia. O conhecimento das variações da artéria subclávia é fundamental, pois as artérias da região cervical lateral são importantes para a obtenção de retalhos em cirurgias plásticas e reconstrutivas. A avaliação radiológica pré-operatória dos pedículos pode ajudar na escolha do desenho ideal do retalho, prevenir complicações isquêmicas e ajudar a melhorar o resultado geral do tratamento.

From source to sink: mechanistic insight of photoassimilates synthesis and partitioning under high temperature and elevated [CO2].

Photosynthesis is the vital metabolism of the plant affected by abiotic stress such as high temperature and elevated [CO2] levels, which ultimately affect the source-sink relationship. Triose phosphate, the primary precursor of carbohydrate (starch and sucrose) synthesis in the plant, depends on environmental cues. The synthesis of starch in the chloroplasts of leaves (during the day), the transport of photoassimilates (sucrose) from source to sink, the loading and unloading of photoassimilates, and the accumulation of starch in the sink tissue all require a highly regulated network and communication system within the plant. These processes might be affected by high-temperature stress and elevated [CO2] conditions. Generally, elevated [CO2] levels enhance plant growth, photosynthetic rate, starch synthesis, and accumulation, ultimately diluting the nutrient of sink tissues. On the contrary, high-temperature stress is detrimental to plant development affecting photosynthesis, starch synthesis, sucrose synthesis and transport, and photoassimilate accumulation in sink tissues. Moreover, these environmental conditions also negatively impact the quality attributes such as grain/tuber quality, cooking quality, nutritional status in the edible parts and organoleptic traits. In this review, we have attempted to provide an insight into the source-sink relationship and the sugar metabolites synthesized and utilized by the plant under elevated [CO2] and high-temperature stress. This review will help future researchers comprehend the source-sink process for crop growth under changing climate scenarios.

Physiological and molecular insights on wheat responses to heat stress.

Increasing temperature is a key component of global climate change, affecting crop growth and productivity worldwide. Wheat is a major cereal crop grown in various parts of the globe, which is affected severely by heat stress. The morphological parameters affected include germination, seedling establishment, source-sink activity, leaf area, shoot and root growth. The physiological parameters such as photosynthesis, respiration, leaf senescence, water and nutrient relation are also affected by heat. At the cellular level, heat stress leads to the generation of reactive oxygen species that disrupt the membrane system of thylakoid, chloroplast and plasma membrane. The deactivation of the photosystem, reduction in photosynthesis and inactivation of rubisco affect the production of photoassimilates and their allocation. This ultimately affects anthesis, grain filling, size, number and maturity of wheat grains, which hamper crop productivity. The interplay of various systems comprising antioxidants and hormones plays a crucial role in imparting heat stress tolerance in wheat. Thus, implementation of various omics technologies could foster in-depth insights on heat stress effects, eventually devising heat stress mitigation strategies by conventional and modern breeding to develop heat-tolerant wheat varieties. This review provides an integrative view of heat stress responses in wheat and also discusses approaches to develop heat-tolerant wheat varieties.

Reflectance based non-destructive determination of colour and ripeness of tomato fruits.

The preference and quality of tomato fruit are primarily determined by its apparent colour and appearance. Non-destructive and rapid methods for assessment of tomato colour and ripeness are therefore of immense significance. This study was conducted to identify reflectance-based indices and to develop models for the non-destructive determination of colour and ripeness (maturity) of tomato fruits. Tomato fruits of two varieties and two hybrids, representing different ripening stages were investigated. Fruits were either harvested directly from the plants or they were picked up from the lots stored at 25 °C. Reflectance from individual fruit was recorded in a spectrum ranging from 350 to 2500 nm. These fruits at different ripening stages were ranked on a relative ripening score (0.0-8.5). Obtained data (reflectance and ripening score) were subjected to chemometric analysis. In total, six models were developed. The first-best model was based on the index R521 (reflectance at wavelength 521 nm) i.e., y (colour/ripeness) = - 2.456 ln (x) - 1.093 where x is R521. This model had a root mean standard error of prediction (RMSEP) ≥ 0.86 and biasness = - 0.09. The second-best model y = 2.582 ln (x) - 0.805 was based on the index R546 (x) and had RMSEP ≥ 0.89 and biasness = 0.10. Models could bifurcate tomatoes into basic ripening stages and also red and beyond red tomato fruits from other stages across the varieties/hybrids and ripening conditions [for plant harvested (fresh) and stored (aged) fruits]. Findings will prove useful in developing simple and thereby cost-effective tools for rapid screening/sorting of tomato fruits based on their colour or ripeness not only for basic research (phenotyping) but also for the purpose of processing, value-addition, and pharmaceutical usages. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12298-022-01126-2.

Body status and blood metabolites profiles during resumption of postpartum ovarian activity in yak (Poephagus grunniens).

We examined the changes in body weight (BW), back-fat thickness (BFT) and blood metabolites in relation to postpartum (PP) ovarian activity status in twenty female yaks raised under semi-intensive system. BFT and ovarian activities, like follicle development, ovulation (OV) and corpus luteum (CL) development, were monitored from 4 to 15 weeks (wk) PP using ultrasonography. Resumption of ovarian activity was confirmed with ovulation of dominant follicle (DF) and subsequent CL development, and >1 ng/ml progesterone concentration in blood plasma sample after 1week of ovulation. Yaks were further classified as cyclic (with CL), acyclic (without CL), and cystic (with >25 mm follicular cyst; FC). Within 20 weeks PP, 60% yaks resumed cyclic ovarian activity, while 25% failed to initiate cycling activity, and 15% developed follicular cysts. In all categories of yak, BW gradually decreased (p < .05) till nadir; however, nadir reached earlier (p < .05) in acyclic yaks. BFT differed (p < .05) among the yak groups, but it tended to be higher in cyclic yaks as compared to acyclic and cystic. No difference (p > .05) in non-esterified fatty acids (NEFA) values was found among the different categories of yaks, whereas, beta-hydroxy butyrate (BHB) levels were higher in cystic animals as compared to acyclic and cyclic. Blood glucose levels decreased in all yaks during initial 2 weeks after calving. Our findings suggest that yaks with low BW, BFT and glucose levels, and higher BHB values were at risk of delayed resumption of ovarian activity and concomitant development of follicular cysts.

Sprout suppression on potato: need to look beyond CIPC for more effective and safer alternatives.

World over, potatoes are being stored at 8-12 °C (85-90 % RH). This is the most common way of long-term (up to 6 to 9 months) storage of potatoes. The benefit of storing the potatoes within the temperature range of 8-12 °C is minimum accumulation of sugars in stored potato tubers. In sub-temperate, sub-tropical and tropical countries of the world, short-term (3 to 4 months) storage of potatoes is being done by non-refrigerated traditional/on-farm methods. These short- and long-term storage methods keep the stored potatoes suitable not only for table purpose but also for processing. However, once the natural dormancy period of potato is over, the prevailing temperatures in these storage methods favour sprouting and sprout growth. Therefore, use of some sprout suppressant to check the sprout growth becomes essential under these methods of potato storage. CIPC [Isopropyl N-(3-chlorophenyl) carbamate] is the most wide spread and commonly used sprout suppressant on potatoes. CIPC has been in use for more than 50 years and research carried out over such a long period use of CIPC has not only enhanced our understanding of its properties and chemistry but also about the production and toxicological status of its metabolites/degradation products. Today, various safety issues and concerns have surfaced primarily due to continuous and long-term use of CIPC. This review presents an appraisal on CIPC and explains the reasons for the long-time dependence on this chemical as a potato sprout suppressant. Issues like maximum residue limit and acceptable daily intake limit are being discussed for CIPC. This article brings an update on practical aspects of potato storage, residue levels of CIPC, efficacy of CIPC as sprout suppressant and health and environmental safety issues linked with CIPC and its metabolites. The aim of this article is to find possible solutions, way outs and future plans that can make the sprout suppression of potatoes safer and more risk free.

Voltage-sensor transitions of the inward-rectifying K+ channel KAT1 indicate a latching mechanism biased by hydration within the voltage sensor.

The Kv-like (potassium voltage-dependent) K(+) channels at the plasma membrane, including the inward-rectifying KAT1 K(+) channel of Arabidopsis (Arabidopsis thaliana), are important targets for manipulating K(+) homeostasis in plants. Gating modification, especially, has been identified as a promising means by which to engineer plants with improved characteristics in mineral and water use. Understanding plant K(+) channel gating poses several challenges, despite many similarities to that of mammalian Kv and Shaker channel models. We have used site-directed mutagenesis to explore residues that are thought to form two electrostatic countercharge centers on either side of a conserved phenylalanine (Phe) residue within the S2 and S3 α-helices of the voltage sensor domain (VSD) of Kv channels. Consistent with molecular dynamic simulations of KAT1, we show that the voltage dependence of the channel gate is highly sensitive to manipulations affecting these residues. Mutations of the central Phe residue favored the closed KAT1 channel, whereas mutations affecting the countercharge centers favored the open channel. Modeling of the macroscopic current kinetics also highlighted a substantial difference between the two sets of mutations. We interpret these findings in the context of the effects on hydration of amino acid residues within the VSD and with an inherent bias of the VSD, when hydrated around a central Phe residue, to the closed state of the channel.

The phosphoinositide PI(3,5)P2 mediates activation of mammalian but not plant TPC proteins: functional expression of endolysosomal channels in yeast and plant cells.

Two-pore channel proteins (TPC) encode intracellular ion channels in both animals and plants. In mammalian cells, the two isoforms (TPC1 and TPC2) localize to the endo-lysosomal compartment, whereas the plant TPC1 protein is targeted to the membrane surrounding the large lytic vacuole. Although it is well established that plant TPC1 channels activate in a voltage- and calcium-dependent manner in vitro, there is still debate on their activation under physiological conditions. Likewise, the mode of animal TPC activation is heavily disputed between two camps favoring as activator either nicotinic acid adenine dinucleotide phosphate (NAADP) or the phosphoinositide PI(3,5)P2. Here, we investigated TPC current responses to either of these second messengers by whole-vacuole patch-clamp experiments on isolated vacuoles of Arabidopsis thaliana. After expression in mesophyll protoplasts from Arabidopsis tpc1 knock-out plants, we detected the Arabidopsis TPC1-EGFP and human TPC2-EGFP fusion proteins at the membrane of the large central vacuole. Bath (cytosolic) application of either NAADP or PI(3,5)P2 did not affect the voltage- and calcium-dependent characteristics of AtTPC1-EGFP. By contrast, PI(3,5)P2 elicited large sodium currents in hTPC2-EGFP-containing vacuoles, while NAADP had no such effect. Analogous results were obtained when PI(3,5)P2 was applied to hTPC2 expressed in baker's yeast giant vacuoles. Our results underscore the fundamental differences in the mode of current activation and ion selectivity between animal and plant TPC proteins and corroborate the PI(3,5)P2-mediated activation and Na(+) selectivity of mammalian TPC2.

Role of internal atmosphere on fruit ripening and storability-a review.

Concentrations of different gases and volatiles present or produced inside a fruit are determined by the permeability of the fruit tissue to these compounds. Primarily, surface morphology and anatomical features of a given fruit determine the degree of permeance across the fruit. Species and varietal variability in surface characteristics and anatomical features therefore influence not only the diffusibility of gases and volatiles across the fruits but also the activity and response of various metabolic and physiological reactions/processes regulated by these compounds. Besides the well-known role of ethylene, gases and volatiles; O2, CO2, ethanol, acetaldehyde, water vapours, methyl salicylate, methyl jasmonate and nitric oxide (NO) have the potential to regulate the process of ripening individually and also in various interactive ways. Differences in the prevailing internal atmosphere of the fruits may therefore be considered as one of the causes behind the existing varietal variability of fruits in terms of rate of ripening, qualitative changes, firmness, shelf-life, ideal storage requirement, extent of tolerance towards reduced O2 and/or elevated CO2, transpirational loss and susceptibility to various physiological disorders. In this way, internal atmosphere of a fruit (in terms of different gases and volatiles) plays a critical regulatory role in the process of fruit ripening. So, better and holistic understanding of this internal atmosphere along with its exact regulatory role on various aspects of fruit ripening will facilitate the development of more meaningful, refined and effective approaches in postharvest management of fruits. Its applicability, specially for the climacteric fruits, at various stages of the supply chain from growers to consumers would assist in reducing postharvest losses not only in quantity but also in quality.

Novel insights into drought-induced regulation of ribosomal genes through DNA methylation in chickpea.

Modifications within the epigenome of an organism in response to external environmental conditions allow it to withstand the hostile stress factors. Drought in chickpea is a severely limiting abiotic stress factor which is known to cause huge yield loss. To analyse the methylome of chickpea in response to drought stress conditions and how it affects gene expression, we performed whole-genome bisulfite sequencing (WGBS) and RNA-seq of two chickpea genotypes which contrast for drought tolerance. It was observed that the mCHH was most variable under drought stress and the drought tolerant (DT) genotype exhibited substantial genome-wide hypomethylation as compared to the drought sensitive (DS) genotype. Specifically, there was substantial difference in gene expression and methylation for the ribosomal genes for the tolerant and sensitive genotypes. The differential expression of these genes was in complete agreement with earlier reported transcriptomes in chickpea. Many of these genes were hypomethylated (q < 0.01) and downregulated under drought stress (p < 0.01) in the sensitive genotype. The gene RPS6 (ribosomal protein small subunit) was found to be downregulated and hypomethylated in the drought sensitive genotype which could possibly lead to reduced ribosomal biosynthesis. This study provides novel insights into regulation of drought-responsive genes in chickpea.

Identification of Climate-Smart Bread Wheat Germplasm Lines with Enhanced Adaptation to Global Warming.

Bread wheat (Triticum aestivum L.) is widely grown in sub-tropical and tropical areas and, as such, it is exposed to heatstress especially during the grain filling period (GFP). Global warming has further affected its production and productivity in these heat-stressed environments. We examined the effects of heatstress on 18 morpho-physiological and yield-related traits in 96 bread wheat accessions. Heat stress decreased crop growth and GFP, and consequently reduced morphological and yield-related traits in the delayed sown crop. A low heat susceptibility index and high yield stability were used for selecting tolerant accessions. Under heatstress, the days to 50% anthesis, flag-leaf area, chlorophyll content, normalized difference vegetation index (NDVI), thousand grain weight (TGW), harvest index and grain yield were significantly reduced both in tolerant and susceptible accessions. The reduction was severe in susceptible accessions (48.2% grain yield reduction in IC277741). The plant height, peduncle length and spike length showeda significant reduction in susceptible accessions, but a non-significant reduction in the tolerant accessions under the heatstress. The physiological traits like the canopy temperature depression (CTD), plant waxiness and leaf rolling were increased in tolerant accessions under heatstress. Scanning electron microscopy of matured wheat grains revealed ultrastructural changes in endosperm and aleurone cells due to heat stress. The reduction in size and density of large starch granules is the major cause of the yield and TGW decrease in the heat-stress-susceptible accessions. The most stable and high-yielding accessions, namely, IC566223, IC128454, IC335792, EC576707, IC535176, IC529207, IC446713 and IC416019 were identified as the climate-smart germplasm lines. We selected germplasm lines possessing desirable traits as potential parents for the development of bi-parent and multi-parent mapping populations.

The Arabidopsis central vacuole as an expression system for intracellular transporters: functional characterization of the Cl-/H+ exchanger CLC-7.

Functional characterization of intracellular transporters is hampered by the inaccessibility of animal endomembranes to standard electrophysiological techniques. Here, we used Arabidopsis mesophyll protoplasts as a novel heterologous expression system for the lysosomal chloride­proton exchanger CLC-7 from rat. Following transient expression of a rCLC-7:EGFP construct in isolated protoplasts, the fusion protein efficiently targeted to the membrane of the large central vacuole, the lytic compartment of plant cells. Membrane currents recorded from EGFP-positive vacuoles were almost voltage independent and showed time-dependent activation at elevated positive membrane potentials as a hallmark. The shift in the reversal potential of the current induced by a decrease of cytosolic pH was compatible with a 2Cl(-)/1H(+) exchange stoichiometry. Mutating the so-called gating glutamate into alanine (E245A) uncoupled chloride fluxes from the movement of protons, transforming the transporter into a chloride channel-like protein. Importantly, CLC-7 transport activity in the vacuolar expression system was recorded in the absence of the auxiliary subunit Ostm1, differently to recent data obtained in Xenopus oocytes using a CLC-7 mutant with partial plasma membrane expression. We also show that plasma membrane-targeted CLC-7(E245A) is non-functional in Xenopus oocytes when expressed without Ostm1. In summary, our data suggest the existence of an alternative CLC-7 operating mode, which is active when the protein is not in complex with Ostm1. The vacuolar expression system has the potential to become a valuable tool for functional studies on intracellular ion channels and transporters from animal cells.

Modulation of plant TPC channels by polyunsaturated fatty acids.

Polyunsaturated fatty acids (PUFAs) are powerful modulators of several animal ion channels. It is shown here that PUFAs strongly affect the activity of the Slow Vacuolar (SV) channel encoded by the plant TPC1 gene. The patch-clamp technique was applied to isolated vacuoles from carrot taproots and Arabidopsis thaliana mesophyll cells and arachidonic acid (AA) was chosen as a model molecule for PUFAs. Our study was extended to different PUFAs including the endogenous alpha-linolenic acid (ALA). The addition of micromolar concentrations of AA reversibly inhibited the SV channel decreasing the maximum open probability and shifting the half activation voltage to positive values. Comparing the effects of different PUFAs, it was found that the length of the lipophilic acyl chain, the number of double bonds and the polar head were critical for channel modulation.The experimental data can be reproduced by a simple three-state model, in which PUFAs do not interact directly with the voltage sensors but affect the voltage-independent transition that leads the channel from the open state to the closed configuration. The results indicate that lipids play an important role in co-ordinating ion channel activities similar to what is known from animal cells.

Determination of insecticidal Cry1Ab protein in soil collected in the final growing seasons of a nine-year field trial of Bt-maize MON810.

Cultivation of genetically modified maize (Bt-maize; event MON810) producing recombinant δ-endotoxin Cry1Ab, leads to introduction of the insecticidal toxin into soil by way of root exudates and plant residues. This study investigated the fate of Cry1Ab in soil under long-term Bt-maize cultivation in an experimental field trial performed over nine growing seasons on four South German field sites cultivated with MON810 and its near isogenic non Bt-maize variety. Cry1Ab protein was quantified in soil (<2 mm size) using an in-house validated ELISA method. The assay was validated according to the criteria specified in European Commission Decision 2002/657/EC. The assay enabled quantification of Cry1Ab protein at a decision limit (CCα) of 2.0 ng Cry1Ab protein g(-1) soil with analytical recovery in the range 49.1-88.9%, which was strongly correlated with clay content. Cry1Ab protein was only detected on one field site at concentrations higher than the CCα, with 2.91 and 2.57 ng Cry1Ab protein g(-1) soil in top and lower soil samples collected 6 weeks after the eighth growing season. Cry1Ab protein was never detected in soil sampled in the spring before the next farming season at any of the four experimental sites. No experimental evidence for accumulation or persistence of Cry1Ab protein in different soils under long-term Bt-maize cultivation can be drawn from this field study.

The fading distinctions between classical patterns of ripening in climacteric and non-climacteric fruit and the ubiquity of ethylene-An overview.

The process of fruit ripening is normally viewed distinctly in climacteric and non-climacteric fruits. But, many fruits such as guava, melon, Japanese plum, Asian pear and pepper show climacteric as well as non-climacteric behaviour depending on the cultivar or genotype. Investigations on in planta levels of CO2 and ethylene at various stages of fruits during ripening supported the role and involvement of changes in the rate of respiration and ethylene production in non-climacteric fruits such as strawberry, grapes and citrus. Non-climacteric fruits are also reported to respond to the exogenous application of ethylene. Comparative analysis of plant-attached and plant-detached fruits did not show similarity in their ripening behaviour. This disparity is being explained in view of 1. Hypothetical ripening inhibitor, 2. Differences in the production, release and endogenous levels of ethylene, 3. Sensitivity of fruits towards ethylene and 4. Variations in the gaseous microenvironment among fruits and their varieties. Detailed studies on genetic and inheritance patterns along with the application of '-omics' research indicated that ethylene-dependent and ethylene-independent pathways coexist in both climacteric and non-climacteric fruits. Auxin levels also interact with ethylene in regulating ripening. These findings therefore reveal that the classification of fruits based on climacteric rise and/or ethylene production status is not very distinct or perfect. However, presence of a characteristic rise in CO2 levels and a burst in ethylene production in some non-climacteric fruits as well as the presence of system 2 of ethylene production point to a ubiquitous role for ethylene in fruit ripening.

Integrated approach towards acrylamide reduction in potato-based snacks: A critical review.

Acrylamide is a process contaminant and neurotoxic with growing evidence of cancer in human. Potato-based products majorly contribute towards acrylamide dietary intake thereby posing major food safety threat that necessitates formulation of acrylamide reduction strategies. This review highlights the recent research work on acrylamide formation mechanism, dietary intake, toxicity and potential reduction strategies at various levels in the food supply chain to ensure safety of potato-based products. Acrylamide formation in potato-based products depends on several factors involved in potato supply chain. Depending on the variety, application of nitrogen and sulphur fertilization may show positive, negative, or no effect on acrylamide formation. Heat and water stress faced by potato crops may increase the risk of acrylamide formation in processed products. Various pre-processing (e.g., blanching, chemical treatments etc.) and processing (e.g., methods, temperature, time) strategies may also reduce acrylamide formation (37-98%) in potato-based products at commercial and domestic levels. The acrylamide reduction strategies from farm to fork level have been discussed with special emphasis on mechanism of chemical treatments with pictorial representation.

Genome-wide identification and expression analysis of the GRAS gene family in response to drought stress in chickpea (Cicer arietinum L.).

The GRAS (gibberellic acid insensitive, repressor of GAI and scarecrow) transcription factors (TFs) regulate diverse biological processes involved in plant growth and development. These TFs are also known to regulate gene expression in response to various abiotic stress factors like cold, drought, etc. In chickpea one of the most devastating abiotic stress factors is terminal drought. The GRAS TF family has not been characterized in chickpea (Cicer arietinum L.) until now. In this study, we report 46 GRAS TF genes (CaGRAS genes) in the chickpea genome. The CaGRAS proteins were categorized into nine subfamilies based on their phylogenetic relationship with known GRAS members of Arabidopsis and soybean. The PAT subfamily was the largest consisting of ten CaGRAS members whereas the LAS subfamily was the smallest with only one member. Gene duplication analysis revealed that segmental duplication was the primary reason for the expansion of this gene family within the chickpea genome. The gene expression levels of CaGRAS genes were analysed using two different chickpea varieties contrasting for drought tolerance trait, i.e., ICC 4958 (drought tolerant) and ICC 1882 (drought sensitive). On exposure to drought stress, the two chickpea genotypes, exhibited differential drought response, which was quantified and estimated in terms of differences in leaf relative water content (RWC). The well-watered or control plants of the drought tolerant variety were able to maintain a higher leaf RWC by the end of the drought stress period, whereas the control plants of the drought sensitive variety continued to show a decline in leaf RWC. The two genotypes also differed in their root morphologies, under well-watered and drought stress conditions. The gene expression analysis revealed a potential role of PAT, SCR, SCL3 and SHR GRAS members in the regulation of differential response to drought, in the root tissues, for both the genotypes. CaGRAS 12 (SCR) was identified as a drought-responsive GRAS TF gene, which could serve as a potential candidate gene for utilization in developing chickpea varieties with improved drought tolerance. This study demonstrates the drought-responsive expression of CaGRAS genes in chickpea and also describes the morpho-physiological response of chickpea plants to drought stress conditions. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-021-03104-z.

Mechanistic Concept of Physiological, Biochemical, and Molecular Responses of the Potato Crop to Heat and Drought Stress.

Most cultivated potatoes are tetraploid, and the tuber is the main economic part that is consumed due to its calorific and nutritional values. Recent trends in climate change led to the frequent occurrence of heat and drought stress in major potato-growing regions worldwide. The optimum temperature for tuber production is 15-20 °C. High-temperature and water-deficient conditions during the growing season result in several morphological, physiological, biochemical, and molecular alterations. The morphological changes under stress conditions may affect the process of stolon formation, tuberization, and bulking, ultimately affecting the tuber yield. This condition also affects the physiological responses, including an imbalance in the allocation of photoassimilates, respiration, water use efficiency, transpiration, carbon partitioning, and the source-sink relationship. The biochemical responses under stress conditions involve maintaining ionic homeostasis, synthesizing heat shock proteins, achieving osmolyte balance, and generating reactive oxygen species, ultimately affecting various biochemical pathways. Different networks that include both gene regulation and transcription factors are involved at the molecular level due to the combination of hot and water-deficient conditions. This article attempts to present an integrative content of physio-biochemical and molecular responses under the combined effects of heat and drought, prominent factors in climate change. Taking into account all of these aspects and responses, there is an immediate need for comprehensive screening of germplasm and the application of appropriate approaches and tactics to produce potato cultivars that perform well under drought and in heat-affected areas.