Identification and functional characterization of the npc-2-like domain containing rust effector protein that suppresses cell death in plants.

The MD-2-related lipid-recognition (ML/Md-2) domain is a lipid/sterol-binding domain that are involved in sterol transfer and innate immunity in eukaryotes. Here we report a genome-wide survey of this family, identifying 84 genes in 30 fungi including plant pathogens. All the studied species were found to have varied ML numbers, and expansion of the family was observed in Rhizophagus irregularis (RI) with 33 genes. The molecular docking studies of these proteins with cholesterol derivatives indicate lipid-binding functional conservation across the animal and fungi kingdom. The phylogenetic studies among eukaryotic ML proteins showed that Puccinia ML members are more closely associated with animal (insect) npc2 proteins than other fungal ML members. One of the candidates from leaf rust fungus Puccinia triticina, Pt5643 was PCR amplified and further characterized using various studies such as qRT-PCR, subcellular localization studies, yeast functional complementation, signal peptide validation, and expression studies. The Pt5643 exhibits the highest expression on the 5th day post-infection (dpi). The confocal microscopy of Pt5643 in onion epidermal cells and N. benthamiana shows its location in the cytoplasm and nucleus. The functional complementation studies of Pt5643 in npc2 mutant yeast showed its functional similarity to the eukaryotic/yeast npc2 gene. Furthermore, the overexpression of Pt5643 also suppressed the BAX, NEP1, and H2O2-induced program cell death in Nicotiana species and yeast. Altogether the present study reports the novel function of ML domain proteins in plant fungal pathogens and their possible role as effector molecules in host defense manipulation.

Evolutionary analysis of tonoplast intrinsic proteins (TIPs) unraveling the role of TIP3s in plant seed development.

Tonoplast intrinsic proteins (TIPs) are crucial in facilitating the transportation of water and various small solutes across biological membranes. The evolutionary path and functional roles of TIPs is poorly understood in plants. In the present study, a total of 976 TIPs were identified in 104 diverse species and subsequently studied to trace their lineage-specific evolutionary path and tissue-specific function. Interestingly, TIPs were found to be absent in lower forms such as algae and fungi and they evolved later in primitive plants like bryophytes. Bryophytes possess a distant class of TIPs, denoted as TIP6, which is not found in higher plants. The aromatic/arginine (ar/R) selectivity filter found in TIP6 of certain liverworts share similarity with hybrid intrinsic protein (HIP), suggesting an evolutionary kinship. As plants evolved to more advanced forms, TIPs diversified into five different sub-groups (TIP1 to TIP5). Notably, TIP5 is a sub-group unique to angiosperms. The evolutionary history of the TIP subfamily reveals an interesting observation that the TIP3 subgroup has evolved within seed-bearing Spermatophyta. Further, TIPs exhibit tissue-specific expression that is conserved within various plant species. Specifically, the TIP3s were found to be exclusively expressed in seeds. Quantitative PCR analysis of TIP3s showed gradually increasing expression in soybean seed developmental stages. The expression of TIP3s in different plant species was also found to be gradually increasing during seed maturation. The results presented here address the knowledge gap concerning the evolutionary background of TIPs, specifically TIP3 in plants, and provide valuable insights for a deeper comprehension of the functions of TIPs in plants.

Silicon improves salt resistance by enhancing ABA biosynthesis and aquaporin expression in Nicotiana tabacum L.

Silicon (Si) can significantly improve the salt tolerance of plants, but its mechanism remains unclear. In this study, role of abscisic acid (ABA) in Si derived salt resistance in tobacco seedling was investigated. Under salt stress, the photosynthetic rate, stomatal conductance, and transpiration rate of tobacco seedlings were reduced by 86.17%, 80.63%, and 67.54% respectively, resulting in a decrease in biomass. The application of Si found to mitigate these stress-induced markers. However, positive role of Si was mainly attributed to the enhanced expression of aquaporin genes, which helped in enhancing root hydraulic conductance (Lpr) and ultimately maintaining the leaf relative water content (RWC). Moreover, sodium tungstate, an ABA biosynthesis inhibitor, was used to test the role of ABA on Si-regulating Lpr. The results indicated that the improvement of Lpr by Si was diminished in the presence of ABA inhibitor. In addition, it was observed that the ABA content was increased due to the Si-upregulated of ABA biosynthesis genes, namely NtNCED1 and NtNCED5. Conversely, the expression of ABA metabolism gene NtCYP7O7A was found to be reduced by Si. Together, this study suggested that Si increased ABA content, leading to enhanced efficiency of water uptake by the roots, ultimately facilitating an adequate water supply to maintain leaf water balance. As a result, there was an improvement in salt resistance in tobacco seedling.

Saffron, a Potential Bridge between Nutrition and Disease Therapeutics: Global Health Challenges and Therapeutic Opportunities.

Plants are an important source of essential bioactive compounds that not only have a beneficial role in human health and nutrition but also act as drivers for shaping gut microbiome. However, the mechanism of their functional attributes is not fully understood despite their significance. One such important plant is Crocus sativus, also known as saffron, which possesses huge medicinal, nutritional, and industrial applications like food and cosmetics. The importance of this plant is grossly attributed to its incredible bioactive constituents such as crocins, crocetin, safranal, picrocrocin, and glycosides. These bioactive compounds possess a wide range of therapeutic activities against multiple human ailments. Since a huge number of studies have revealed negative unwanted side effects of modern-day drugs, the scientific communities at the global level are investigating a large number of medicinal plants to explore natural products as the best alternatives. Taken into consideration, the available research findings indicate that saffron has a huge scope to be further explored to establish alternative natural-product-based drugs for health benefits. In this review, we are providing an update on the role of bioactive compounds of saffron as therapeutic agents (human disorders and antimicrobial activity) and its nutritional values. We also highlighted the role of omics and metabolic engineering tools for increasing the content of key saffron bioactive molecules for its mass production. Finally, pre-clinical and clinical studies seem to be necessary to establish its therapeutic potential against human diseases.

Unveiling silicon-mediated cadmium tolerance mechanisms in mungbean (Vigna radiata (L.) Wilczek): Integrative insights from gene expression, antioxidant responses, and metabolomics.

Cadmium (Cd), one of the most phytotoxic heavy metals, is a major contributor to yield losses in several crops. Silicon (Si) is recognized for its vital role in mitigating Cd toxicity, however, the specific mechanisms governing this mitigation process are still not fully understood. In the present study, the effect of Si supplementation on mungbean (Vigna radiata (L.) Wilczek) plants grown under Cd stress was investigated to unveil the intricate pathways defining Si derived stress tolerance. Non-invasive leaf imaging technique revealed improved growth, biomass, and photosynthetic efficiency in Si supplemented mungbean plants under Cd stress. Further, physiological and biochemical analysis revealed Si mediated increase in activity of glutathione reductase (GR), ascorbate peroxidase (APX), and catalase (CAT) enzymes involved in reactive oxygen species (ROS) metabolism leading to mitigation of cellular damage and oxidative stress. Untargeted metabolomic analysis using liquid chromatography coupled with mass spectrometry (LC-MS/MS) provided insights into Si mediated changes in metabolites and their respective pathways under Cd stress. Alteration in five different metabolic pathways with major changes in flavanols and flavonoids biosynthesis pathway which is essential for controlling plants antioxidant defense system and oxidative stress management were observed. The information reported here about the effects of Si on photosynthetic efficiency, antioxidant responses, and metabolic changes will be helpful in understanding the Si-mediated resistance to Cd stress in plants.

Aquaporin mediated silicon-enhanced root hydraulic conductance is benefit to cadmium dilution in tobacco seedlings.

Numerous studies shown that silicon (Si) enhanced plants' resistance to cadmium (Cd). Most studies primarily focused on investigating the impact of Si on Cd accumulation. However, there is a lack of how Si enhanced Cd resistance through regulation of water balance. The study demonstrated that Si had a greater impact on increasing fresh weight compared to dry weight under Cd stress. This effect was mainly attributed to Si enhanced plant relative water content (RWC). Plant water content depends on the dynamic balance of water loss and water uptake. Our findings revealed that Si increased transpiration rate and stomatal conductance, leading to higher water loss. This, in turn, negatively impacted water content. The increased water content caused by Si could ascribe to improve root water uptake. The Si treatment significantly increased root hydraulic conductance (Lpr) by 131 % under Cd stress. This enhancement was attributed to Si upregulation genes expression of NtPIP1;1, NtPIP1;2, NtPIP1;3, and NtPIP2;1. Through meticulously designed scientific experiments, this study showed that Si enhanced AQP activity, leading to increased water content that diluted Cd concentration and ultimately improved plant Cd resistance. These findings offered fresh insights into the role of Si in bolstering plant resistance to Cd.

Metalloid transporters in plants: bridging the gap in molecular structure and physiological exaptation.

The rhizosphere contains both essential nutrients and potentially harmful substances for plant growth. Plants, as sessile organisms, must efficiently absorb the necessary nutrients while actively avoiding the uptake of toxic compounds. Metalloids, which are elements that exhibit properties of both metals and nonmetals, can have different effects on plant growth, ranging from being essential and beneficial to being toxic. The toxicity of metalloids in plants arises due to either the dosage of exposure or the specific elemental type. To utilize or detoxify these elements, plants have developed various transporters that regulate their uptake and distribution in plants. Arguably, genomic sequence analysis suggests the presence of such transporter families throughout the plant kingdom, from chlorophytes to higher plants. These transporters form defined families with related transport preferences. The isoforms within these families have evolved with specialized functions regulated by defined selectivity. Hence, understanding transporters' chemistry to atomic detail is important to achieve desired genetic modifications for crop improvement. Here, we outline various adaptations in plant transport systems to deal with metalloids, including their uptake, distribution, detoxification, and homeostasis in plant tissues. Structural parallels are drawn to other nutrient transporter systems to support emerging themes of functional diversity of active sites of transporters, elucidating adaptations of plants to utilize and extrude metalloid concentrations. Considering the observed physiological importance of metalloids, this review intends to highlight the shared and disparate features in metalloid transport systems and their corresponding nutrient transporters.

Silicon regulates phosphate deficiency through involvement of auxin and nitric oxide in barley roots.

MAIN CONCLUSION: Silicon application mitigates phosphate deficiency in barley through an interplay with auxin and nitric oxide, enhancing growth, photosynthesis, and redox balance, highlighting the potential of silicon as a fertilizer for overcoming nutritional stresses. Silicon (Si) is reported to attenuate nutritional stresses in plants, but studies on the effect of Si application to plants grown under phosphate (Pi) deficiency are still very scarce, especially in barley. Therefore, the present work was undertaken to investigate the potential role of Si in mitigating the adverse impacts of Pi deficiency in barley Hordeum vulgare L. (var. BH902). Further, the involvement of two key regulatory signaling molecules--auxin and nitric oxide (NO)--in Si-induced tolerance against Pi deficiency in barley was tested. Morphological attributes, photosynthetic parameters, oxidative stress markers (O2·-, H2O2, and MDA), antioxidant system (enzymatic--APX, CAT, SOD, GR, DHAR, MDHAR as well as non-enzymatic--AsA and GSH), NO content, and proline metabolism were the key traits that were assessed under different treatments. The P deficiency distinctly declined growth of barley seedlings, which was due to enhancement in oxidative stress leading to inhibition of photosynthesis. These results were also in parallel with an enhancement in antioxidant activity, particularly SOD and CAT, and endogenous proline level and its biosynthetic enzyme (P5CS). The addition of Si exhibited beneficial effects on barley plants grown in Pi-deficient medium as reflected in increased growth, photosynthetic activity, and redox balance through the regulation of antioxidant machinery particularly ascorbate-glutathione cycle. We noticed that auxin and NO were also found to be independently participating in Si-mediated improvement of growth and other parameters in barley roots under Pi deficiency. Data of gene expression analysis for PHOSPHATE TRANSPORTER1 (HvPHT1) indicate that Si helps in increasing Pi uptake as per the need of Pi-deficient barley seedlings, and also auxin and NO both appear to help Si in accomplishing this task probably by inducing lateral root formation. These results are suggestive of possible application of Si as a fertilizer to correct the negative effects of nutritional stresses in plants. Further research at genetic level to understand Si-induced mechanisms for mitigating Pi deficiency can be helpful in the development of new varieties with improved tolerance against Pi deficiency, especially for cultivation in areas with Pi-deficient soils.

Silicon, a quasi-essential element: Availability in soil, fertilizer regime, optimum dosage, and uptake in plants.

The essentiality of silicon (Si) has always been a matter of debate as it is not considered crucial for the lifecycles of most plants. But beneficial effects of endogenous Si and its supplementation have been observed in many plants. Silicon plays a pivotal role in alleviating the biotic and abiotic stress in plants by acting as a physical barrier as well as affecting molecular pathways involved in stress tolerance, thus widely considered as "quasi-essential". In soil, most of Si is found in complex forms as mineral silicates which is not available for plant uptake. Monosilicic acid [Si(OH)4] is the only plant-available form of silicon (PAS) present in the soil. The ability of a plant to uptake Si is positively correlated with the PAS concentration of the soil. Since many cultivated soils often lack a sufficient amount of PAS, it has become common practice to supplement Si through the use of Si-based fertilizers in various crop cultivation systems. This review outlines the use of natural and chemical sources of Si as fertilizer, different regimes of Si fertilization, and conclude by identifying the optimum concentration of Si required to observe the beneficial effects in plants. Also, the different mathematical models defining the mineral dynamics for Si uptake at whole plant scale considering various natural factors like plant morphology, mineral distribution, and transporter expression have been discussed. Information provided here will further help in increasing understanding of Si role and thereby facilitate efficient exploration of the element as a fertilizer in crop production.

Genome-Wide Association Study (GWAS) for Identifying SNPs and Genes Related to Phosphate-Induced Phenotypic Traits in Tomato (Solanum lycopersicum L.).

Phosphate (P) is a crucial macronutrient for normal plant growth and development. The P availability in soils is a limitation factor, and understanding genetic factors playing roles in plant adaptation for improving P uptake is of great biological importance. Genome-wide association studies (GWAS) have become indispensable tools in unraveling the genetic basis of complex traits in various plant species. In this study, a comprehensive GWAS was conducted on diverse tomato (Solanum lycopersicum L.) accessions grown under normal and low P conditions for two weeks. Plant traits such as shoot height, primary root length, plant biomass, shoot inorganic content (SiP), and root inorganic content (RiP) were measured. Among several models of GWAS tested, the Bayesian-information and linkage disequilibrium iteratively nested keyway (BLINK) models were used for the identification of single nucleotide polymorphisms (SNPs). Among all the traits analyzed, significantly associated SNPs were recorded for PB, i.e., 1 SNP (SSL4.0CH10_49261145) under control P, SiP, i.e., 1 SNP (SSL4.0CH08_58433186) under control P and 1 SNP (SSL4.0CH08_51271168) under low P and RiP i.e., 2 SNPs (SSL4.0CH04_37267952 and SSL4.0CH09_4609062) under control P and 1 SNP (SSL4.0CH09_3930922) under low P condition. The identified SNPs served as genetic markers pinpointing regions of the tomato genome linked to P-responsive traits. The novel candidate genes associated with the identified SNPs were further analyzed for their protein-protein interactions using STRING. The study provided novel candidate genes, viz. Solyc10g050370 for PB under control, Solyc08g062490, and Solyc08g062500 for SiP and Solyc09g010450, Solyc09g010460, Solyc09g010690, and Solyc09g010710 for RiP under low P condition. These findings offer a glimpse into the genetic diversity of tomato accessions' responses to P uptake, highlighting the potential for tailored breeding programs to develop P-efficient tomato varieties that could adapt to varying soil conditions, making them crucial for sustainable agriculture and addressing global challenges, such as soil depletion and food security.

Prime Editing in Plants: Prospects and Challenges.

Prime editors are reverse transcriptase (RT)-based genome editing tools utilizing double strand break (DSB) free mechanisms to decrease off-target editing in genomes and enhance the efficiency of targeted insertions. Multiple prime editors developed within a short span of time are a testament to the potential of this technique for targeted insertions. This is mainly because of the possibility of generation of all types of mutations including deletions, insertions, transitions and transversions. Prime editing reverses several bottlenecks of gene editing technologies that limit the biotechnological applicability to produce designer crops. The current mini review evaluates the status and evolution of prime editing technique in terms of the types of prime editors available till date up to prime editor 5 and twin prime editors, and the developments in plants in a systematic manner. The various factors affecting prime editing efficiency in plants including the effect of temperature, the pegRNA, and RT template amongst others are discussed in detail. We discuss the obstructions, key challenges, available resolutions, and provide future directions and further improvements feasible to elevate the efficiency in plants.

Structural assessment of OsNIP2;1 highlighted critical residues defining solute specificity and functionality of NIP class aquaporins.

INTRODUCTION: Nodulin-26-like intrinsic proteins (NIPs) are integral membrane proteins belonging to the aquaporin family, that facilitate the transport of neutral solutes across the bilayer. The OsNIP2;1 a member of NIP-III class of aquaporins is permeable to beneficial elements like silicon and hazardous arsenic. However, the atomistic cross-talk of these molecules traversing the OsNIP2;1 channel is not well understood. OBJECTIVE: Due to the lack of genomic variation but the availability of high confidence crystal structure, this study aims to highlight structural determinants of metalloid permeation through OsNIP2;1. METHODS: The molecular simulations, combined with site-directed mutagenesis were used to probe the role of specific residues in the metalloid transport activity of OsNIP2;1. RESULTS: We drew energetic landscape of OsNIP2;1, for silicic and arsenous acid transport. Potential Mean Force (PMF) construction illuminate three prominent energetic barriers for metalloid passage through the pore. One corresponds to the extracellular molecular entry in the channel, the second located on ar/R filter, and the third size constriction in the cytoplasmic half. Comparative PMF for silicic acid and arsenous acid elucidate a higher barrier for silicic acid at the cytoplasmic constrict resulting in longer residence time for silicon. Furthermore, our simulation studies explained the importance of conserved residues in loop-C and loop-D with a direct effect on pore dynamics and metalloid transport. Next we assessed contribution of predicted key residues for arsenic uptake, by functional complementation in yeast. With the aim of reducing arsenic uptake while maintaining beneficial elements uptake, we identified novel OsNIP2;1 mutants with substantial reduction in arsenic uptake in yeast. CONCLUSION: We provide a comprehensive assessment of pore lining residues of OsNIP2;1 with respect to metalloid uptake. The findings will expand mechanistic understanding of aquaporin's metalloid selectivity and facilitate variant interpretation to develop novel alleles with preference for beneficial metalloid species and reducing hazardous ones.

SpeedFlower: a comprehensive speed breeding protocol for indica and japonica rice.

To increase rice yields and feed billions of people, it is essential to enhance genetic gains. However, the development of new varieties is hindered by longer generation times and seasonal constraints. To address these limitations, a speed breeding facility has been established and a robust speed breeding protocol, SpeedFlower is developed that allows growing 4-5 generations of indica and/or japonica rice in a year. Our findings reveal that a high red-to-blue (2R > 1B) spectrum ratio, followed by green, yellow and far-red (FR) light, along with a 24-h long day (LD) photoperiod for the initial 15 days of the vegetative phase, facilitated early flowering. This is further enhanced by 10-h short day (SD) photoperiod in the later stage and day and night temperatures of 32/30 °C, along with 65% humidity facilitated early flowering ranging from 52 to 60 days at high light intensity (800 µmol m-2 s-1). Additionally, the use of prematurely harvested seeds and gibberellic acid treatment reduced the maturity duration by 50%. Further, SpeedFlower was validated on a diverse subset of 198 rice accessions from 3K RGP panel encompassing all 12 distinct groups of Oryza sativa L. classes. Our results confirmed that using SpeedFlower one generation can be achieved within 58-71 days resulting in 5.1-6.3 generations per year across the 12 sub-groups. This breakthrough enables us to enhance genetic gain, which could feed half of the world's population dependent on rice.

Biotechnology and urban agriculture: A partnership for the future sustainability.

The global population is growing rapidly, and with it, the demand for food. In the coming decades, more and more people will be living in urban areas, where land for traditional agriculture is scarce. Urban agriculture can help to meet this growing demand for food in a sustainable way. Urban agriculture is the practice of growing food in urban areas. It can be done on rooftops, balconies, vacant lots, and even in alleyways. Urban agriculture can produce a variety of crops, including fruits, vegetables, and herbs. It can also help to improve air quality, reduce stormwater runoff, and create jobs. Biotechnology can be used to improve the efficiency and sustainability of urban agriculture. Biotechnological tools can be used to develop crops that are resistant to pests and diseases, that are more tolerant of drought and heat, and that have higher yields. Biotechnology can also be used to improve the nutritional value of crops. This review article discusses the need for and importance of urban agriculture, biotechnology, and genome editing in meeting the growing demand for food in urban areas. It also discusses the potential of biotechnology to improve the sustainability of urban agriculture.

Identification of VrNIP2-1 aquaporin with novel selective filter regulating the transport of beneficial as well as hazardous metalloids in mungbean (Vigna radiata L.).

Nodulin 26-like intrinsic protein (NIP) subfamily of aquaporins (AQPs) in plants, is known to be involved in the uptake of metalloids including boron, germanium (Ge), arsenic (As), and silicon (Si). In the present study, a thorough evaluation of 55 AQPs found in the mungbean genome, including phylogenetic distribution, sequence homology, expression profiling, and structural characterization, contributed to the identification of VrNIP2-1 as a metalloid transporter. The pore-morphology of VrNIP2-1 was studied using molecular dynamics simulation. Interestingly, VrNIP2-1 was found to harbor an aromatic/arginine (ar/R) selectivity filter formed with ASGR amino acids instead of GSGR systematically reported in metalloid transporters (NIP2s) in higher plants. Evaluation of diverse cultivars showed a high level of Si accumulation in leaves indicating functional Si transport in mungbean. In addition, heterologous expression of VrNIP2-1 in yeast revealed As(III) and GeO2 transport activity. Similarly, VrNIP2-1 expression in Xenopus oocytes confirmed its Si transport ability. The metalloid transport activity with unique structural features will be helpful to better understand the solute specificity of NIP2s in mungbean and related pulses. The information provided here will also serve as a basis to improve Si uptake while restricting hazardous metalloids like As in plants.

Hemibiotrophic Phytophthora infestans Modulates the Expression of SWEET Genes in Potato (Solanum tuberosum L.).

Sugar Efflux transporters (SWEET) are involved in diverse biological processes of plants. Pathogens have exploited them for nutritional gain and subsequently promote disease progression. Recent studies have implied the involvement of potato SWEET genes in the most devastating late blight disease caused by Phytophthora infestans. Here, we identified and designated 37 putative SWEET genes as StSWEET in potato. We performed detailed in silico analysis, including gene structure, conserved domains, and phylogenetic relationship. Publicly available RNA-seq data was harnessed to retrieve the expression profiles of SWEET genes. The late blight-responsive SWEET genes were identified from the RNA-seq data and then validated using quantitative real-time PCR. The SWEET gene expression was studied along with the biotrophic (SNE1) and necrotrophic (PiNPP1) marker genes of P. infestans. Furthermore, we explored the co-localization of P. infestans resistance loci and SWEET genes. The results indicated that nine transporter genes were responsive to the P. infestans in potato. Among these, six transporters, namely StSWEET10, 12, 18, 27, 29, and 31, showed increased expression after P. infestans inoculation. Interestingly, the observed expression levels aligned with the life cycle of P. infestans, wherein expression of these genes remained upregulated during the biotrophic phase and decreased later on. In contrast, StSWEET13, 14, and 32 didn't show upregulation in inoculated samples suggesting non-targeting by pathogens. This study underscores these transporters as prime P. infestans targets in potato late blight, pivotal in disease progression, and potential candidates for engineering blight-resistant potato genotypes.

Overexpression of peanut (Arachis hypogaea L.) AhGRFi gene enhanced root growth inhibition under exogenous NAA treatment in Arabidopsis thaliana.

The 14-3-3 protein is a kind of evolutionary ubiquitous protein family highly conserved in eukaryotes. Initially, 14-3-3 proteins were reported in mammalian nervous tissues, but in the last decade, their role in various metabolic pathways in plants established the importance of 14-3-3 proteins. In the present study, a total of 22 14-3-3 genes, also called general regulatory factors (GRF), were identified in the peanut (Arachis hypogaea) genome, out of which 12 belonged to the ε group, whereas 10 of them belonged to the non- ε-group. Tissue-specific expression of identified 14-3-3 genes were studied using transcriptome analysis. The peanut AhGRFi gene was cloned and transformed into Arabidopsis thaliana. The investigation of subcellular localization indicated that AhGRFi is localized in the cytoplasm. Overexpression of the AhGRFi gene in transgenic Arabidopsis showed that under exogenous 1-naphthaleneacetic acid (NAA) treatment, root growth inhibition in transgenic plants was enhanced. Further analysis indicated that the expression of auxin-responsive genes IAA3, IAA7, IAA17, and SAUR-AC1 was upregulated and GH3.2 and GH3.3 were downregulated in transgenic plants, but the expression of GH3.2, GH3.3, and SAUR-AC1 showed opposite trends of change under NAA treatment. These results suggest that AhGRFi may be involved in auxin signaling during seedling root development. An in-depth study of the molecular mechanism of this process remains to be further explored.

Drought and Oxidative Stress in Flax (Linum usitatissimum L.) Entails Harnessing Non-Canonical Reference Gene for Precise Quantification of qRT-PCR Gene Expression.

Flax (Linum usitatissimum L.) is a self-pollinating, annual, diploid crop grown for multi-utility purposes for its quality oil, shining bast fiber, and industrial solvent. Being a cool (Rabi) season crop, it is affected by unprecedented climatic changes such as high temperature, drought, and associated oxidative stress that, globally, impede its growth, production, and productivity. To precisely assess the imperative changes that are inflicted by drought and associated oxidative stress, gene expression profiling of predominant drought-responsive genes (AREB, DREB/CBF, and ARR) was carried out by qRT-PCR. Nevertheless, for normalization/quantification of data obtained from qRT-PCR results, a stable reference gene is mandatory. Here, we evaluated a panel of four reference genes (Actin, EF1a, ETIF5A, and UBQ) and assessed their suitability as stable reference genes for the normalization of gene expression data obtained during drought-induced oxidative stress in flax. Taking together, from the canonical expression of the proposed reference genes in three different genotypes, we report that EF1a as a stand-alone and EF1a and ETIF5A in tandem are suitable reference genes to be used for the real-time visualization of cellular impact of drought and oxidative stress on flax.