Developmental Responses of Root Hairs to Mg Deficiency

Genome-wide identification of MGT gene family in soybean (Glycine max) and their expression analyses under magnesium stress conditions

BACKGROUND

Magnesium (Mg) is essential for plant growth and development and plays critical roles in physiological and biochemical processes. Mg deficiency adversely affects growth of plants by limiting shoot and root development, disturbing the structure and membranes of the grana, reducing photosynthesis efficiency, and lowering net CO2 assimilation. The MGT (Magnesium transporter) family is responsible for the absorption and transportation of magnesium in plants. Although the MGT family has been identified in different plant species, research regarding the soybean MGT genes is limited.

RESULTS

In the current study, a total of 39 MGT genes distributed on 17 different chromosomes were identified in soybean. Phylogenetic analysis classified GmMGTs into three subgroups, NIPA, MRS2/MGT, and CorA, which showed little homology with MGTs of Arabidopsis thaliana and Oryza sativa members and clustered tightly with GmMGTs. Gene structure and conserved motif analysis also confirmed similar grouping in GmMGTs. The expansion of the GmMGT members in NIPA and MRS2/MGT was predicted, while CorA was identified as the most conserved group in G. max. Segmental duplication under purifying selection pressure was identified as the major driving force in the expansion of MGTs in soybean. GmMGTs showed diverse tissue-specific and stress-response expression patterns due to the presence of stress-related cis-regulatory elements in their promoter regions. Under Mg-deficiency and surplus stress conditions, a decrease in root length, shoot length, and root and shoot fresh as well dry weight in susceptible genotypes showed the variegated expression of MGTs in soybean genotypes. Furthermore, the upregulation of GmMGT2 and GmMGT29 in tolerant genotypes in response to Mg-deficiency as well as surplus stress conditions in leaves suggested the essential role of GmMGT genes in the absorption and transportation of Mg in soybean leaves.

CONCLUSION

This study presents a comprehensive analysis of the MGT gene family in soybean, providing insights into their evolutionary relationships, gene classification, protein structures, and expression patterns under both Mg deficiency and Mg surplus conditions.

Exploring the puzzle of reactive oxygen species acting on root hair cells

Reactive oxygen species (ROS) are essential signaling molecules that enable cells to respond rapidly to a range of stimuli. The ability of plants to recognize various stressors, incorporate a variety of environmental inputs, and initiate stress-response networks depends on ROS. Plants develop resilience and defensive systems as a result of these processes. Root hairs are central components of root biology since they increase the surface area of the root, anchor it in the soil, increase its ability to absorb water and nutrients, and foster interactions between microorganisms. In this review, we specifically focused on root hair cells and we highlighted the identification of ROS receptors, important new regulatory hubs that connect ROS production, transport, and signaling in the context of two hormonal pathways (auxin and ethylene) and under low temperature environmental input related to nutrients. As ROS play a crucial role in regulating cell elongation rates, root hairs are rapidly gaining traction as a very valuable single plant cell model for investigating ROS homeostasis and signaling. These promising findings might soon facilitate the development of plants and roots that are more resilient to environmental stressors.

Understanding signaling pathways governing the polar development of root hairs in low-temperature, nutrient-deficient environments

Plants exposed to freezing and above-freezing low temperatures must employ a variety of strategies to minimize fitness loss. There is a considerable knowledge gap regarding how mild low temperatures (around 10 °C) affect plant growth and developmental processes, even though the majority of the molecular mechanisms that plants use to adapt to extremely low temperatures are well understood. Root hairs (RH) have become a useful model system for studying how plants regulate their growth in response to both cell-intrinsic cues and environmental inputs. Here, we'll focus on recent advances in the molecular mechanisms underpinning Arabidopsis thaliana RH growth at mild low temperatures and how these discoveries may influence our understanding of nutrient sensing mechanisms by the roots. This highlights how intricately linked mechanisms are necessary for plant development to take place under specific circumstances and to produce a coherent response, even at the level of a single RH cell.

Microstructural and physiological responses to cadmium stress under different nitrogen levels in Populus cathayana females and males

Although increasing attention has been paid to the relationships between heavy metal and nitrogen (N) availability, the mechanism underlying adaptation to cadmium (Cd) stress in dioecious plants has been largely overlooked. This study examined Cd accumulation, translocation and allocation among tissues and cellular compartments in Populus cathayana Rehder females and males. Both leaf Cd accumulation and root-to-shoot Cd translocation were significantly greater in females than in males under a normal N supply, but they were reduced in females and enhanced in males under N deficiency. The genes related to Cd uptake and translocation, HMA2, YSL2 and ZIP2, were strongly induced by Cd stress in female roots and in males under a normal N supply. Cadmium largely accumulated in the leaf blades of females and in the leaf veins of males under a normal N supply, while the contrary was true under N deficiency. Furthermore, Cd was mainly distributed in the leaf epidermis and spongy tissues of males, and in the leaf palisade tissues of females. Nitrogen deficiency increased Cd allocation to the spongy tissues of female leaves and to the palisade tissues of males. In roots, Cd was preferentially distributed to the epidermis and cortices in both sexes, and also to the vascular tissues of females under a normal N supply but not under N deficiency. These results suggested that males possess better Cd tolerance compared with females, even under N deficiency, which is associated with their reduced root-to-shoot Cd translocation, specific Cd distribution in organic and/or cellular compartments, and enhanced antioxidation and ion homeostasis. Our study also provides new insights into engineering woody plants for phytoremediation.