Biology subjects

Joshi, A. K.

Publications and source records attributed to Joshi, A. K..

3 recordsLinked to original sources

bioRxiv2023

Spatio-temporal evaluation of drought adaptation in wheat revealed NDVI and MTSI as powerful tools for selecting tolerant genotypes

ContextWater stress is fast becoming a major limiting factor for wheat production. Hence, identifying drought tolerant genotypes is critical for sustaining the food supply chain. However, there are no phenotypic markers or statistical models available that may be employed for the efficient selection of field grown drought tolerant wheat genotypes. ObjectivesWe evaluated wheat genotypes to (1) identify novel sources of drought tolerance (2) understand underlying adaptation mechanisms of drought tolerance (3) identify phenotypic markers and a stable model for the selection of drought tolerant genotypes MethodsOne hundred ninety-six diverse wheat genotypes were evaluated at three different locations in India: Banaras Hindu University (BHU), Varanasi (E1 and E3: control; E2 and E4: drought); Agharkar Research Institute (ARI), Pune (E5 and E7: control; E6 and E8: drought) and Borlaug Institute for South Asia (BISA), Jabalpur (E9 and E11: control; E10 and E12: drought) for various agronomic, physiological and yield traits for two consecutive years. Drought was imposed at the heading stage (Z59) by withholding irrigation for four weeks until the moisture reading reached <45% than the control (100%). ResultsThe performance of all genotypes significantly declined under drought at all the locations. Normalized difference vegetation index (NDVI) significantly correlated (r = 0.41** and 0.36**) with the grain yield under drought during maturity. At the same time, there was no association under control conditions (r = 0.07 and 0.10) at the BHU center during 2020-21 and 2021-22, respectively. Stress indices, such as geometric mean productivity (GMP) and stress tolerance index (STI), showed a high correlation (r= 0.89** and r = 0.88**, respectively) with the grain yield under drought and were effective in differentiating drought tolerant genotypes. GGE bi-plots discriminated the environments (observed obtuse angle between E3 with E6 and E9, E4 with E6 and E9) having negative relation and cross-over interaction for grain yield. Further, the multi-trait stability index (MTSI) identified 29 stable genotypes across all environments and was predicted as the most accurate model due to its fewer Root Mean Square Prediction Difference (RMSPD) values. ConclusionNDVI is a useful high throughput screening tool under drought and MTSI is an effective method for selecting stable wheat genotypes across different water stressed locations. ImplicationsThe identified tools (NDVI), method (MTSI), and tolerant genotypes appear to be valuable resources that together will be useful in the ongoing breeding programs to enhance the drought tolerance of wheat. HighlightsO_LIDrought stress significantly reduces wheat production globally. C_LIO_LINDVI serves as a useful tool for high throughput screening under drought for field-based experiments. C_LIO_LIAMMI, GGE, WAASBY and MTSI plots are effective in detecting GEI effects. C_LIO_LIMTSI is a reliable tool for selecting stable and high mean performers. C_LI

plant biology↗

bioRxiv2022

Allele mining, evolutionary genetic analysis of TaHKT1;5 gene and evaluation of salinity stress in selected lines of wheat.

This study reports the novel allelic diversity in HKT 1;5 gene (High Affinity Potassium Transporter) in bread wheat and its phylogenetic relationship among the paralogs/orthologs of in Triticum aestivum and its wild relatives. HKT 1;5 gene is a known and pivotal gene associated with the salinity tolerance in plants upon the discrimination of K+ over Na+ in leaves without change in Na+ concentration in root. This gene was sequenced in a diverse collection of bread wheat, durum wheat, wild relatives, and ditelosomic lines. Sequence analysis in bread wheat led to the identification of four alleles, which could be distinguished by number of SNPs. Sequence comparison between monocot bread wheat and dicot Arabidopsis thaliana revealed that the HKT1;5 gene is conserved at level of exonic regions; however, the presence of transposable elements especially in intronic regions is further intriguing towards evolutionary relatedness. Two paralogous or major alleles observed in Triticum monoccum and Aegilops tauschii were further categorized as sub-alleles based on their SNPs comparison. This gene was absent in T. urartu in accordance with existing evidence, while it was found in A. speltoides (an allelic variant) with a few base pairs insertion in the exon1 region causing a frameshift mutation with an altered amino acids and genomic database mining unveiled additional alleles in this species. Ditelosomic lines with 4DL and 4DS chromosomes revealed a higher similarity with bread and durum wheat respectively. Phylogenetic studies of HKT1;5 orthologs from different Poaceae species revealed the occurrence of five different ortholog groups with taxonomic consistency. Phenotyping based salinity stress experiment distinguished the unknown lines for salinity tolerance and sensitiveness in comparison with known reference lines and possible allelic comparison was made. The salinity stress analysis further revealed that some known drought/heat tolerance lines showed slightly better salinity tolerance with mean values and variability of traits than known saline tolerant wheat line at controlled ambient.

genetics↗

bioRxiv2019

Unveiling the transcriptome complexity of the High- and Low- Zinc & Iron accumulating Indian wheat (Triticum aestivum L.) cultivars

Development of Zinc (Zn), Iron (Fe) and other minerals rich grains along with various stress tolerance and susceptible (STR) wheat genotype, will help to reduce globally spread malnutrition problem. Current study deals with transcriptome profiling of 4 high- and 3 low- Zn & Fe accumulating wheat genotypes (HZFWGs) and (LZFWGs). Functional characterization of expressed and high and low specific genes, accompanied by metabolic pathways analysis reveals, phenylpropanoid biosynthesis, and other associated pathways are mainly participating in plant stress defense mechanism in both genotypes. Chlorophyll synthesis, Zn & Fe binding, metal ion transport, and ATP-Synthase coupled transport mechanism are highly active in HZFWGs while in LZFWGs ribosomal formation, biomolecules binding activities and secondary metabolite biosynthesis. Transcripts accountable for minerals uptake and purine metabolism in HZFWGs are highly enriched. Identified transcripts may be used for marker-assisted selection and breeding to develop minerals rich crops.

bioinformatics↗