Biology subjects

Pandey, B. K.

Publications and source records attributed to Pandey, B. K..

3 recordsLinked to original sources

bioRxiv2023

Glutaredoxin regulation of primary root growth confers early drought stress tolerance in pearl millet

Seedling root traits impact plant establishment under challenging environments. Pearl millet is one of the most heat and drought tolerant cereal crops that provides a vital food source across the sub-Saharan Sahel region. Pearl millets early root system features a single fast-growing primary root which we hypothesize is an adaptation to the Sahelian climate. Using crop modelling, we demonstrate that early drought stress is an important constraint in agrosystems in the Sahel where pearl millet was domesticated. Furthermore, we show that increased pearl millet primary root growth is correlated with increased early water stress tolerance in field conditions. Genetics including GWAS and QTL approaches identify genomic regions controlling this key root trait. Combining gene expression data, re-sequencing and re-annotation of one of these genomic regions identified a glutaredoxin-encoding gene PgGRXC9 as the candidate stress resilience root growth regulator. Functional characterization of its closest Arabidopsis homolog AtROXY19 revealed a novel role for this glutaredoxin (GRX) gene clade in regulating cell elongation. In summary, our study suggests a conserved function for GRX genes in conferring root cell elongation and enhancing resilience of pearl millet to its Sahelian environment.

plant biology↗

bioRxiv2021

Genotypic variation in soil penetration by maize roots is negatively related to ethylene-induced thickening

Radial expansion is a classic response of roots to mechanical impedance that has generally been assumed to aid penetration. We analysed the response of maize nodal roots to impedance to test the hypothesis that radial expansion is not related to the ability of roots to cross a compacted soil layer. Genotypes varied in their ability to cross the compacted layer, and those with a steeper approach to the compacted layer or less radial expansion in the compacted layer were more likely to cross the layer and achieve greater depth. Root radial expansion was due to cortical cell size expansion, while cortical cell file number remained constant. Genotypes and nodal root classes that exhibited radial expansion upon encountering the compacted soil layer also thickened in response to exogenous ethylene in hydroponic culture, i.e. radial expansion in response to ethylene was correlated with the thickening response to impedance in soil. We propose that ethylene insensitive roots, i.e. those that do not thicken and are able to overcome impedance, have a competitive advantage under mechanically impeded conditions as they can maintain their elongation rates. We suggest that prolonged exposure to ethylene could function as a stop signal for axial root growth.

plant biology↗

bioRxiv2018

OsJAZ9 overexpression improves potassium deficiency tolerance in rice by modulating jasmonic acid levels and signaling

Potassium (K) which makes around 2-10% of plants total dry biomass, when become deficient, makes the plants highly susceptible to both abiotic and biotic stresses. Recent evidences suggest overlapping transcriptional responses to K deficiency and Jasmonate (JA) treatment in plants. However, a link between these responses was missing. Notably, K deficiency and JA application produce similar phenotypic and transcriptional responses. Here, we used molecular, physiological and morphological studies to analyze the role of OsJAZ9 in JA homeostasis, K deficiency and sheath blight resistance. We raised OsJAZ9 overexpression, knockdown, translational reporter and C-terminal deleted translational reporter lines in rice to establish the role of JA signaling in K ion homeostasis and OsJAZ9 as a critical component of JA signaling for K deficiency response. OsJAZ9 overexpression and knockdown provide K deficiency tolerance and sensitivity, respectively, by modulating various K transporters and root system architecture. Furthermore, RNA Seq and JA profiling revealed an elevation of JA responsive genes and JA levels in OsJAZ9 OE lines under K deficiency. Our data provide clear evidence on the crucial role of JAZ repressor, OsJAZ9 in improving K deficiency tolerance in rice by altering JA levels and signaling.

plant biology↗