Differential characterization of physiological and biochemical responses during drought stress in finger millet varieties

Abstract

Drought is the most perilous abiotic stress that affects finger millet growth and productivity worldwide. For the successful production of finger millet, selection of drought tolerant varieties is necessary and critical stages under drought stress, germination and early seedling growth, ought to be fully understood. This study investigated the physiological and biochemical responses of six finger millet varieties (GBK043137, GBK043128, GBK043124, GBK043122, GBK043094 and GBK043050) under mannitol-induced drought stress. Seeds were germinated in sterile soil and irrigated with various concentrations of mannitol (200, 400 and 600 mM) for 2 weeks. In a comparative analysis relative water content (RWC), chlorophyll, proline and malondialdehyde (MDA) contents were measured to obtain the physiological and biochemical characteristics of drought stress. The results showed that increased levels of drought stress seriously decreased germination and early seedling growth of finger millet varieties. However, root growth was increased. In addition, exposition to drought stress triggered a significant decrease in relative water content and chlorophyll content reduction, and the biochemical parameters assay showed less reduction in RWC. Furthermore, oxidative damage indicating parameters, such as proline concentration and MDA content, increased. Varieties GBK043137 and GBK043094 were less affected by drought than the other varieties as shown by significant changes in their physiological parameters. Our findings reveal the differences between the physiological and biochemical responses of finger millet to drought and are vital for breeding and selecting drought tolerant varieties of finger millet. Further, genomic and molecular investigations need to be undertaken to gain a deeper insight into the detailed mechanisms of drought tolerance in finger millet.

Integration of transcriptomic and proteomic analyses for finger millet [Eleusine coracana (L.) Gaertn.] in response to drought stress

“…Recently, finger millet has attracted more attention due to its nutritional profile and hardiness during stress conditions [ 29 ]. In this study, drought caused finger millet to undergo significant molecular changes in order to protect itself from stress, many of which have previously been shown to take place in other drought-tolerant species [ 30 ]. A more detailed understanding of the transcriptome and proteome changes which take place in finger millet during drought stress is the key to understanding its response mechanism and identifying key regulatory genes.…”

“…These proteins play a role in the drought resistance of finger millet. It shows that most of the genes are transcription factors, and the drought stress of finger millet may be related to chloroplast photosynthesis [ 30 ]. Additionally, many drought-related proteins were found to be enriched in cellular metabolic process, protein turnover and hydrolase activity.…”

“…It has also been shown that higher water use contributes more to shoot biomass, while higher transpiration efficiency contributes more to grain yield [ 12 ]. Meanwhile, the characterization of physiological and biochemical responses of finger millet varieties during drought stress has also been studied, providing an important basis for selecting drought-tolerant varieties [ 13 ]. However, the drought tolerance mechanisms at the level of individual genes and proteins are still unclear.…”

Insights into the plant responses to drought and decoding the potential of root associated microbiome for inducing drought tolerance

“…In this connection, Hazman and Brown (2018) have correlated drought tolerance in rice cultivars with the increase in lateral root branching and pronounced lignification of the stele. Mannitol‐induced drought stress in finger millet varieties also enhanced root growth, however, a marked effect on the seed germination, early growth, relative water content (RWC), and chlorophyll content was also observed (Mukami et al, 2019). Moreover, root types and microbial associations determine the formation of rhizosheath—a layer of soil that strongly remains attached to the root system.…”

Molecular and Physiological Perspectives of Abscisic Acid Mediated Drought Adjustment Strategies

“…Typically, plants need water from seedling to the reproductive stage to transport nutrients, for photosynthesis, and to maintain the turgidity of cell walls and various cellular processes [10]. Not having adequate water poses a severe threat to seed germination and seedling growth in plants with decreasing osmotic potential [11][12][13][14][15][16]. Prolonged drought condition reduces uptake of nutrients by root, leaf water potential, transpiration rate, water-use efficiency and stomatal conductance essential for both vegetative and reproductive growth [11].…”