Recent Insights into Auxin-Mediated Molecular Cross Talk Events Associated with Regulation of Root Growth and Architecture During Abiotic Stress in Plants

Expansins are structural proteins prevalent in cell walls, participate in cell growth and stress responses by interacting with internal and external signals perceived by the genetic networks of plants. Herein, we investigated the Brassica rapa expansin-like B1 (BrEXLB1) interaction with phytohormones (IAA, ABA, Ethephon, CK, GA3, SA, and JA), genes (Bra001852, Bra001958, and Bra003006), biotic (Turnip mosaic Virus (TuMV), Pectobacterium carotovorum, clubroot disease), and abiotic stress (salt, oxidative, osmotic, and drought) conditions by either cDNA microarray or qRT-PCR assays. In addition, we also unraveled the potential role of BrEXLB1 in root growth, drought stress response, and seed germination in transgenic Arabidopsis and B. rapa lines. The qRT-PCR results displayed that BrEXLB1 expression was differentially influenced by hormones, and biotic and abiotic stress conditions; upregulated by IAA, ABA, SA, ethylene, drought, salt, osmotic, and oxidative conditions; and downregulated by clubroot disease, P. carotovorum, and TuMV infections. Among the tissues, prominent expression was observed in roots indicating the possible role in root growth. The root phenotyping followed by confocal imaging of root tips in Arabidopsis lines showed that BrEXLB1 overexpression increases the size of the root elongation zone and induce primary root growth. Conversely, it reduced the seed germination rate. Further analyses with transgenic B. rapa lines overexpressing BrEXLB1 sense (OX) and antisense transcripts (OX-AS) confirmed that BrEXLB1 overexpression is positively associated with drought tolerance and photosynthesis during vegetative growth phases of B. rapa plants. Moreover, the altered expression of BrEXLB1 in transgenic lines differentially influenced the expression of predicted BrEXLB1 interacting genes like Bra001852 and Bra003006. Collectively, this study revealed that BrEXLB1 is associated with root development, drought tolerance, photosynthesis, and seed germination.

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Plant hormone cross-talk: the pivot of root growth

Journal of Experimental Botany ◽

10.1093/jxb/eru534 ◽

2015 ◽

Vol 66 (4) ◽

pp. 1113-1121 ◽

Cited By ~ 104

Author(s):

Elena Pacifici ◽

Laura Polverari ◽

Sabrina Sabatini

Keyword(s):

Root Growth ◽

Cross Talk ◽

Plant Hormone

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Root plasticity under abiotic stress

Plant Physiology ◽

10.1093/plphys/kiab392 ◽

2021 ◽

Author(s):

Rumyana Karlova ◽

Damian Boer ◽

Scott Hayes ◽

Christa Testerink

Keyword(s):

Abiotic Stress ◽

Root Growth ◽

Root System ◽

System Architecture ◽

Root System Architecture ◽

Root Anatomy ◽

Soil Conditions ◽

Root Plasticity ◽

Cellular Mechanisms ◽

Aerenchyma Formation

Abstract Abiotic stresses increasingly threaten existing ecological and agricultural systems across the globe. Plant roots perceive these stresses in the soil and adapt their architecture accordingly. This review provides insights into recent discoveries showing the importance of root system architecture and plasticity for the survival and development of plants under heat, cold, drought, salt, and flooding stress. In addition, we review the molecular regulation and hormonal pathways involved in controlling root system architecture plasticity, main root growth, branching and lateral root growth, root hair development and formation of adventitious roots. Several stresses affect root anatomy by causing aerenchyma formation, lignin and suberin deposition, and Casparian strip modulation. Roots can also actively grow towards favourable soil conditions and avoid environments detrimental to their development. Recent advances in understanding the cellular mechanisms behind these different root tropisms are discussed. Understanding root plasticity will be instrumental for the development of crops that are resilient in the face of abiotic stress.

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An arginine decarboxylase gene PtADC from Poncirus trifoliata confers abiotic stress tolerance and promotes primary root growth in Arabidopsis

Journal of Experimental Botany ◽

10.1093/jxb/erq463 ◽

2011 ◽

Vol 62 (8) ◽

pp. 2899-2914 ◽

Cited By ~ 96

Author(s):

Jing Wang ◽

Pei-Pei Sun ◽

Chun-Li Chen ◽

Yin Wang ◽

Xing-Zheng Fu ◽

...

Keyword(s):

Abiotic Stress ◽

Root Growth ◽

Stress Tolerance ◽

Abiotic Stress Tolerance ◽

Primary Root ◽

Arginine Decarboxylase ◽

Poncirus Trifoliata ◽

Primary Root Growth

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Tomato Root Growth Inhibition by Salinity and Cadmium Is Mediated By S-Nitrosative Modifications of ROS Metabolic Enzymes Controlled by S-Nitrosoglutathione Reductase

Biomolecules ◽

10.3390/biom9090393 ◽

2019 ◽

Vol 9 (9) ◽

pp. 393 ◽

Cited By ~ 4

Author(s):

Jedelská ◽

Kraiczová ◽

Berčíková ◽

Činčalová ◽

Luhová ◽

...

Keyword(s):

Abiotic Stress ◽

Root Growth ◽

Growth Inhibition ◽

Protein S ◽

Cadmium Stress ◽

Root Growth Inhibition ◽

Post Translational Modification ◽

Tomato Root ◽

Wild Tomato Species ◽

Ros Metabolism

S-nitrosoglutathione reductase (GSNOR) exerts crucial roles in the homeostasis of nitric oxide (NO) and reactive nitrogen species (RNS) in plant cells through indirect control of S-nitrosation, an important protein post-translational modification in signaling pathways of NO. Using cultivated and wild tomato species, we studied GSNOR function in interactions of key enzymes of reactive oxygen species (ROS) metabolism with RNS mediated by protein S-nitrosation during tomato root growth and responses to salinity and cadmium. Application of a GSNOR inhibitor N6022 increased both NO and S-nitrosothiol levels and stimulated root growth in both genotypes. Moreover, N6022 treatment, as well as S-nitrosoglutathione (GSNO) application, caused intensive S-nitrosation of important enzymes of ROS metabolism, NADPH oxidase (NADPHox) and ascorbate peroxidase (APX). Under abiotic stress, activities of APX and NADPHox were modulated by S-nitrosation. Increased production of H2O2 and subsequent oxidative stress were observed in wild Solanum habrochaites, together with increased GSNOR activity and reduced S-nitrosothiols. An opposite effect occurred in cultivated S. lycopersicum, where reduced GSNOR activity and intensive S-nitrosation resulted in reduced ROS levels by abiotic stress. These data suggest stress-triggered disruption of ROS homeostasis, mediated by modulation of RNS and S-nitrosation of NADPHox and APX, underlies tomato root growth inhibition by salinity and cadmium stress.

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Ectopic expression of the sesame MYB transcription factor SiMYB305 promotes root growth and modulates ABA-mediated tolerance to drought and salt stresses in Arabidopsis

AoB Plants ◽

10.1093/aobpla/plz081 ◽

2019 ◽

Vol 12 (1) ◽

Cited By ~ 2

Author(s):

Komivi Dossa ◽

Marie A Mmadi ◽

Rong Zhou ◽

Aili Liu ◽

Yuanxiao Yang ◽

...

Keyword(s):

Abiotic Stress ◽

Root Growth ◽

Stress Tolerance ◽

Cell Damage ◽

Abiotic Stress Tolerance ◽

Stomatal Closure ◽

Ectopic Expression ◽

Myb Transcription Factor ◽

Marker Genes ◽

Crop Species

Abstract An increasing number of candidate genes related to abiotic stress tolerance are being discovered and proposed to improve the existing cultivars of the high oil-bearing crop sesame (Sesamum indicum L.). However, the in planta functional validation of these genes is remarkably lacking. In this study, we cloned a novel sesame R2-R3 MYB gene SiMYB75 which is strongly induced by drought, sodium chloride (NaCl), abscisic acid (ABA) and mannitol. SiMYB75 is expressed in various sesame tissues, especially in root and its protein is predicted to be located in the nucleus. Ectopic over-expression of SiMYB75 in Arabidopsis notably promoted root growth and improved plant tolerance to drought, NaCl and mannitol treatments. Furthermore, SiMYB75 over-expressing lines accumulated higher content of ABA than wild-type plants under stresses and also increased sensitivity to ABA. Physiological analyses revealed that SiMYB75 confers abiotic stress tolerance by promoting stomatal closure to reduce water loss; inducing a strong reactive oxygen species scavenging activity to alleviate cell damage and apoptosis; and also, up-regulating the expression levels of various stress-marker genes in the ABA-dependent pathways. Our data suggested that SiMYB75 positively modulates drought, salt and osmotic stresses responses through ABA-mediated pathways. Thus, SiMYB75 could be a promising candidate gene for the improvement of abiotic stress tolerance in crop species including sesame.

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