Genetic characterization and linkage analysis of spotted leaf 6,liguleless and lax panicle traits in mutant rice.

Phenotypic mutants are valuable resources for elucidating the function of genes responsible for their expression. This study examined mutant rice strains expressing three traits: spotted leaf 6 (spl6), lax panicle (lax), and liguleless (lg). In the mutant, the spl6 phenotype was a genetically programmed lesion-mimicking mutation (LMM) that displayed spontaneously scattered spots across the leaf surface. In the lg trait, the plant lacked a collar region, and there were no auricles and ligules at the junction of the leaf blade and leaf sheath. The lax panicle trait manifested as sparely arranged spikelets resulting from the terminal spikelet with no lateral spikelets, which caused a drastic reduction of the total seed number in the mutant. All three mutant genes were genetically recessive and had nuclear gene regulation. The dihybrid segregation of the lg gene was classified independently according to the Mendelian 9:3:3:1 dihybrid segregation ratio in the F2 generation, suggesting that the lg gene is not linked to the same chromosome as the lax and spl6 genes. On the other hand, spl6 and lax were not assorted independently, indicating that they are closely linked on chromosome 1 in rice. Additional linkage analysis from the recombination of spl6 and lax genes reconfirmed that the two genes were ~9.4 cM away from each other. The individual single-gene mutant plant from one plant with a three-gene mutation (spl6, lax, and lg) was isolated and characterized, which will be a crucial resource for the gene cloning and molecular characterization of these genes.

Characterization of Plant-Derived Natural Inhibitors of Dipeptidyl Peptidase-4 as Potential Antidiabetic Agents: A Computational Study.

Diabetes, characterized by elevated blood sugar levels, poses significant health and economic risks, correlating with complications like cardiovascular disease, kidney failure, and blindness. Dipeptidyl peptidase-4 (DPP-4), also referred to as T-cell activation antigen CD26 (EC 3.4.14.5.), plays a crucial role in glucose metabolism and immune function. Inhibiting DPP-4 was anticipated as a potential new therapy for diabetes. Therefore, identification of plant-based natural inhibitors of DPP-4 would help in eradicating diabetes worldwide. Here, for the identification of the potential natural inhibitors of DPP-4, we developed a phytochemicals library consisting of over 6000 phytochemicals detected in 81 medicinal plants that exhibited anti-diabetic potency. The library has been docked against the target proteins, where isorhamnetin, Benzyl 5-Amino-5-deoxy-2,3-O-isopropyl-alpha-D-mannofuranoside (DTXSID90724586), and 5-Oxo-7-[4-(trifluoromethyl) phenyl]-4H,6H,7H-[1,2]thiazolo[4,5-b]pyridine 3-carboxylic acid (CHEMBL3446108) showed binding affinities of -8.5, -8.3, and -8.3 kcal/mol, respectively. These compounds exhibiting strong interactions with DPP-4 active sites (Glu205, Glu206, Tyr547, Trp629, Ser630, Tyr662, His740) were identified. ADME/T and bioactivity predictions affirmed their pharmacological safety. Density functional theory calculations assessed stability and reactivity, while molecular dynamics simulations demonstrated persistent stability. Analyzing parameters like RMSD, RG, RMSF, SASA, H-bonds, MM-PBSA, and FEL confirmed stable protein-ligand compound formation. Principal component analysis provided structural variation insights. Our findings suggest that those compounds might be possible candidates for developing novel inhibitors targeting DPP-4 for treating diabetes.

Identification of medicinal plant-based phytochemicals as a potential inhibitor for SARS-CoV-2 main protease (Mpro) using molecular docking and deep learning methods.

Highly transmissive and rapidly evolving Coronavirus disease-2019 (COVID-19), a viral disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), triggered a global pandemic, which is one of the most researched viruses in the academia. Effective drugs to treat people with COVID-19 have yet to be developed to reduce mortality and transmission. Studies on the SARS-CoV-2 virus identified that its main protease (Mpro) might be a potential therapeutic target for drug development, as this enzyme plays a key role in viral replication. In search of potential inhibitors of Mpro, we developed a phytochemical library consisting of 2431 phytochemicals from 104 Korean medicinal plants that exhibited medicinal and antioxidant properties. The library was screened by molecular docking, followed by revalidation by re-screening with a deep learning method. Recurrent Neural Networks (RNN) computing system was used to develop an inhibitory predictive model using SARS coronavirus Mpro dataset. It was deployed to screen the top 12 compounds based on their docked binding affinity that ranged from -8.0 to -8.9 kcal/mol. The top two lead compounds, Catechin gallate and Quercetin 3-O-malonylglucoside, were selected depending on inhibitory potency against Mpro. Interactions with the target protein active sites, including His41, Met49, Cys145, Met165, and Thr190 were also examined. Molecular dynamics simulation was performed to analyze root mean square deviation (RMSD), root mean square fluctuation (RMSF), radius of gyration (RG), solvent accessible surface area (SASA), and number of hydrogen bonds. Results confirmed the inflexible nature of the docked complexes. Absorption, distribution, metabolism, excretion, and toxicity (ADMET), as well as bioactivity prediction confirmed the pharmaceutical activities of the lead compound. Findings of this research might help scientists to optimize compatible drugs for the treatment of COVID-19 patients.

Genetic analysis of a DROOPING LEAF mutant allele dl-6 associated with a twisted and folded leaf base caused by a deficiency in midrib development in rice.

The failure of midrib formation in rice leaf blades results in the drooping leaf (dl) phenotype. A normal DROOPING LEAF (DL) gene is necessary for leaf homeotic transformation, which affects midrib and pistil development. Genetic analysis was performed on a new drooping leaf (dl) mutant named dl-6 in rice. The dl-6 allelic mutant exhibited drooping leaves that were severely folded and twisted at the base but had normal flower structure. The dl-6 allele is a nuclear recessive trait that fits a 3:1 Mendelian segregation ratio. The dl-6 mutant leaves displayed an abnormal main vein (midrib-less) with undeveloped aerenchyma and vascular bundles, resulting in severe leaf drooping. The lack of a midrib in dl-6 caused weak mechanical support, which resulted in folding at the collar junction of the leaf base and downward bending. Through genetic mapping, the dl-6 allele was identified at approximately 28.2 cM on rice chromosome 3. The allele was caused by mutations within the DL (LOC_Os03g11600.1) gene, with specific amino acid substitutions and additions in the encoded protein of the YABBY transcription factor. The dl-6 mutant is a recessive allele encoding a dysfunctional YABBY transcription factor that regulates leaf midrib development and aerenchymatous clear cell structures, leading to a drooping leaf phenotype in rice.

Stomatal development and genetic expression in Arabidopsis thaliana L.

Stomata are turgor-driven microscopic epidermal valves of land plants. The controlled opening and closing of the valves are essential for regulating the gas exchange and minimizing the water loss and eventually regulating the internal temperatures. Stomata are also a major site of pathogen/microbe entry and plant defense system. Maintaining proper stomatal density, distribution, and development are pivotal for plant survival. Arabidopsis is a model plant to study molecular basis including signaling pathways, transcription factors, and key components for the growth and development of specific organs as well as the whole plant. It has intensively been studied and found out the driver for the development and patterning of stomata. In this review, we have explained how the MAPK signaling cascade is controlled by TOO MANY MOUTHS (TMM) receptor-like protein and the Erecta (ER) receptor-like kinase family. We have also summarized how this MAPK cascade affects primary transcriptional regulators to finally activate the main three basic Helix-Loop-Helix (bHLH) principal transcription factors, which are required for the development and patterning of stomata. Moreover, regulatory activity and cellular connections of polar proteins and environmentally mediated ligand-receptor interactions in the stomatal developmental pathways have extensively been discussed in this review.

Rice Lesion Mimic Mutants (LMM): The Current Understanding of Genetic Mutations in the Failure of ROS Scavenging during Lesion Formation.

Rice lesion mimic mutants (LMMs) form spontaneous lesions on the leaves during vegetative growth without pathogenic infections. The rice LMM group includes various mutants, including spotted leaf mutants, brown leaf mutants, white-stripe leaf mutants, and other lesion-phenotypic mutants. These LMM mutants exhibit a common phenotype of lesions on the leaves linked to chloroplast destruction caused by the eruption of reactive oxygen species (ROS) in the photosynthesis process. This process instigates the hypersensitive response (HR) and programmed cell death (PCD), resulting in lesion formation. The reasons for lesion formation have been studied extensively in terms of genetics and molecular biology to understand the pathogen and stress responses. In rice, the lesion phenotypes of most rice LMMs are inherited according to the Mendelian principles of inheritance, which remain in the subsequent generations. These rice LMM genetic traits have highly developed innate self-defense mechanisms. Thus, although rice LMM plants have undesirable agronomic traits, the genetic principles of LMM phenotypes can be used to obtain high grain yields by deciphering the efficiency of photosynthesis, disease resistance, and environmental stress responses. From these ailing rice LMM plants, rice geneticists have discovered novel proteins and physiological causes of ROS in photosynthesis and defense mechanisms. This review discusses recent studies on rice LMMs for the Mendelian inheritances, molecular genetic mapping, and the genetic definition of each mutant gene.

Biochemical and histological alterations induced by the smoke of allethrin based mosquito coil on mice model.

BACKGROUND: Mosquito coil (MC) emits insecticide upon burning which provides limited protection against lethal mosquito borne diseases. However, apart from killing the insect, toxicities associated with the inhalation of these insecticides poses severe health hazards. However, the use of MC is increasing day by day in third world countries in particular but, yet to receive enough attention of both policy maker and general public. The current study was aimed to assess the MC smoke induced damage of pulmonary and hepatic tissues along with observing the alterations of several blood biochemical parameters in mice model. METHODS: A total of twenty four Swiss albino mice were allowed to inhale the smoke of allethrin based MC at different duration per day for 120 days. By the end of treatment period, blood sample was drawn from each mouse and blood biochemical parameters including alanine transaminase (ALT), aspartate transaminase (AST), blood urea nitrogen(BUN), serum total protein, cholesterol, low density lipoprotein (LDL) and triglyceride (TG) were analyzed. Intact lung and liver were collected for histological analysis using standard protocol. RESULTS: Biochemical study indicates elevated activity of two hepatic enzymes: ALT (89%), AST (85%), in comparison with the respective control. Increased level of some parameters of lipid profile including cholesterol (36%), LDL (48%) and triglyceride (30%) in smoke inhaled mice is the new finding of this study. On the contrary, the activity of serum total protein and BUN was decreased by 20% and 24%, respectively in inhaled mice. Pulmonary tissue of treated mice shows severe forms of emphysema and hyperplasia, especially in the peripheral region of lung, which is the hallmark of chronic obstructive pulmonary disease (COPD). Histological study of hepatic tissue shows apoptosis mediated damage of hepatocytes along with severe form of necrosis. Infiltration of Inflammatory cells was also observed in both of the organs. CONCLUSION: Results from the present studies suggest that chronic exposure of allethrin based MC is responsible factor for severe health complications such as COPD due to the alterations of the key biochemical parameters of blood and histo-organization of lung and liver.

Comparative phenotypic and physiological characteristics of spotted leaf 6 (spl6) and brown leaf spot2 (bl2) lesion mimic mutants (LMM) in rice.

Spontaneous necrotic lesions were found in a lesion mimic mutant brown leaf spot 2 (bl2) without pathogenic infection. Small spots in the seedlings appeared at the four leaves stage and gradually grew into a large round and black area with a gray center on the leaf surfaces. Lower growth habit and lower agronomic trait values with reduced stature, tiller, and panicle number, as well as lower yield potential were noted in the mutants relative to the trait values of the wild-type plants. Microscopic analysis revealed that mesophyll chloroplast was severely damaged or absent in the spotted area of the mutant leaves. Total chlorophyll content, hydrogen peroxide level, and catalase activity were increased at up to 45 days after germination and were dropped at 60 d in the mutant leaves. However, the total protein contents were reduced slightly with a growth period of up to 45 days and were increased at 60 days after germination. A gradual increment of the total ascorbic acid contents in the mutants were observed with advanced plant age, but increased until 45 days and dropped comparatively at 60 days in the wild-type leaves. Increased gene transcriptions of OsPDI and OsGPX1 were noted in the spotted leaves as compared to the non-spotted leaves of the mutant and wild-type leaves, whereas transcripts of OsTPX were transcribed at lower levels in the spotted leaves as compared to the non-spotted leaves. The genetic nature of the bl2 mutant indicated that the F(1) plants evidenced the wild-type phenotype and that bl2 was governed by a single recessive gene.

Proteome analysis and characterization of phenotypes of lesion mimic mutant spotted leaf 6 in rice.

Rice spotted leaf 6 (spl6) mutant produces lesions caused by spontaneous cell death in the absence of pathogenic infection. Expression of this genetic trait was developmentally programmed. After the tillering stage, small red and brown lesions were initiated in groups on the leaf blade. Eventually, the lesions formed parallel lines along the midrib of the leaf. Under light and transmission electron microscopy, we observed that thylakoid membranes of mesophyll chloroplasts were progressively damaged in the nonspotted section of the mutant leaf. However, chloroplasts were absent in the mesophyll cells of the spotted area of the spl6 mutant. These results indicated that lesion formation of the spl6 mutant might be caused by oxidative burst. Proteome analysis revealed that 159 protein spots were up or downregulated in comparison between spotted leaves of the spl6 mutant plants and normal leaves of the wild type. Among them, protein disulfide isomerase (PDI), transketolase, thioredoxin peroxidase (TPX), ATP synthase, RuBisCO large subunit, and RuBisCO activase small subunit were not identified in the spl6 mutant but were abundant in the wild type. Especially, the absence of TPX and PDI might be the cause of the failure to protect cells against oxidative burst resulting in degradation of the thylakoid membranes and leading to programmed cell death and lesion development.