Abstract
Mineral (Fe/Zn) stress significantly affects fundamental metabolic and physiological responses in plants that results in reduction of plant growth and development. Deficiency of these micronutrients leads to inhibition of photosynthesis by having impact on various crucial biological processes like protein synthesis, primary and secondary metabolism and carbohydrate partitioning between source and sink tissues. In the present study, common bean variety Shalimar French Bean-1 (SFB-1) plants were used as an experimental material and were grown under in vitro condition on four different MGRL media i.e. normal MGRL medium (Control), MGRL without Fe (0-Fe), MGRL without Zinc (0-Zn) and MGRL with excess Zn (300-Zn) for 21days under optimum conditions. Shoot and root tissues from all the treatments were harvested and further subjected to estimation of total chlorophyll, total sugar and extraction of total RNA for differential gene expression of sugar transporter 13 (STP13). We observed significant decrease in total chlorophyll content in samples harvested from mineral stress plants. However, the concentration of total sugar and fold expression of STP13 gene was significantly higher in shoots of Fe/Zn stressed and in roots of 300-Zn plants. We observed higher accumulation of sugar under stress condition that correlated with high expression of sugar transporter 13 (STP 13). Further, we observed decrease in the chlorophyll content under stress conditions. Based on these findings, we propose the role of sugar driven signaling in decreasing photosynthesis in case of common bean. The decrease in photosynthesis is confirmed by observing significant decrease in chlorophyll content in stressed plants.
Highlights
Mineral stress is affecting multiple vital functions in plant cells that are must for the growth and development of a plant
In case of Arabidopsis, under mineral stress conditions sugars were found getting accumulated in the shoots due to reduction in phloem unloading in sink tissue that have affected the expression levels of proteins involved in photosynthesis as such decrease in the photosynthetic activity[8, 9]
This study revealed that the regulation of STP 13expression, total sugar and total chlorophyll content are interrelated and enhances our current understanding of sugar transporter 13 (STP13) function in Phaseolus vulgaris under Fe/Zn stress conditions
Summary
Mineral stress is affecting multiple vital functions in plant cells that are must for the growth and development of a plant. Iron (Fe) and Zinc (Zn) represent the most important micronutrients that arecritical for plant growth and crop yields [1] These micronutrients are directly involved in multiple metabolic pathways and physiological responses, catalyzes the reduction-oxidation reactions, chlorophyll synthesis and photosynthesis, cofactor of many enzymes, playing a key role in transcription and cellular functioning, as are critical for proper growth and development of plants [2]. Both Fe and Zn stress leads to chlorosis in plants that reduces photosynthetic activity [3, 4]. We used common bean variety SFB-1 as a dicot legume crop model
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