Salt Stress Promotes Abscisic Acid Accumulation to Affect Cell Proliferation and Expansion of Primary Roots in Rice

The primary root is the basic component of the root system and plays a key role in early seedling growth in rice. Its growth is easily affected by environmental cues, such as salt stress. Abscisic acid (ABA) plays an essential role in root development, but the molecular mechanism underlying ABA-regulated root growth in response to salt stress remains poorly understood. In this study, we report that salt stress inhibits primary root elongation and promotes primary root swelling. Moreover, salt stress induces the expression of ABA-responsive genes and ABA accumulation in the primary root, revealing that ABA plays an essential role in salt-modulated root growth. Transgenic lines of OsSAPK10-OE and OsABIL2-OE, which constitutively express OsSAPK10 or OsABIL2, with enhanced or attenuated ABA signaling, show increased and decreased sensitivity to salt, correspondingly. Microscopic analysis indicates that salt and ABA inhibits cell proliferation and promotes cell expansion in the root apical meristem. Transcriptome analysis showed that ABA induces the expression of EXPANSIN genes. Further investigations indicate that ABA exerts these effects largely through ABA signaling. Thus, our findings deepen our understanding of the role of ABA in controlling primary root growth in response to salt stress, and this knowledge can be used by breeders to cultivate rice varieties suitable for saline–alkali land.

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CRISPR/Cas9-targeted mutagenesis of OsERA1 confers enhanced responses to abscisic acid and drought stress and increased primary root growth under nonstressed conditions in rice

PLoS ONE ◽

10.1371/journal.pone.0243376 ◽

2020 ◽

Vol 15 (12) ◽

pp. e0243376

Author(s):

Takuya Ogata ◽

Takuma Ishizaki ◽

Miki Fujita ◽

Yasunari Fujita

Keyword(s):

Abscisic Acid ◽

Drought Stress ◽

Stress Response ◽

Root Growth ◽

Primary Root ◽

Targeted Mutagenesis ◽

Negative Regulator ◽

Aba Signaling ◽

Primary Root Growth ◽

Mutant Lines

Abscisic acid (ABA) signaling components play an important role in the drought stress response in plants. Arabidopsis thaliana ENHANCED RESPONSE TO ABA1 (ERA1) encodes the β-subunit of farnesyltransferase and regulates ABA signaling and the dehydration response. Therefore, ERA1 is an important candidate gene for enhancing drought tolerance in numerous crops. However, a rice (Oryza sativa) ERA1 homolog has not been characterized previously. Here, we show that rice osera1 mutant lines, harboring CRISPR/Cas9-induced frameshift mutations, exhibit similar leaf growth as control plants but increased primary root growth. The osera1 mutant lines also display increased sensitivity to ABA and an enhanced response to drought stress through stomatal regulation. These results illustrate that OsERA1 is a negative regulator of primary root growth under nonstressed conditions and also of responses to ABA and drought stress in rice. These findings improve our understanding of the role of ABA signaling in the drought stress response in rice and suggest a strategy to genetically improve rice.

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Under salt stress guard cells rewire ion transport and abscisic acid (ABA) signaling

New Phytologist ◽

10.1111/nph.17376 ◽

2021 ◽

Author(s):

Sohail M. Karimi ◽

Matthias Freund ◽

Brittney M. Wager ◽

Michael Knoblauch ◽

Jörg Fromm ◽

...

Keyword(s):

Abscisic Acid ◽

Salt Stress ◽

Ion Transport ◽

Guard Cells ◽

Aba Signaling

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Function of abscisic acid in maintenance of maize primary root growth under water deficit

10.32469/10355/4459 ◽

2006 ◽

Cited By ~ 1

Author(s):

In-jeong Cho

Keyword(s):

Abscisic Acid ◽

Root Growth ◽

Water Deficit ◽

Primary Root ◽

Primary Root Growth

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Abscisic acid-mediated phytochrome B signaling promotes primary root growth in Arabidopsis

Plant Signaling & Behavior ◽

10.1080/15592324.2018.1473684 ◽

2018 ◽

Vol 13 (5) ◽

pp. e1473684

Author(s):

K.-E. Gil ◽

J.-H. Ha ◽

C.-M. Park

Keyword(s):

Abscisic Acid ◽

Root Growth ◽

Primary Root ◽

Phytochrome B ◽

Primary Root Growth

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Hydrogen peroxide plays an important role in PERK4-mediated abscisic acid-regulated root growth in Arabidopsis

Functional Plant Biology ◽

10.1071/fp18219 ◽

2019 ◽

Vol 46 (2) ◽

pp. 165 ◽

Cited By ~ 15

Author(s):

Xiaonan Ma ◽

Xiaoran Zhang ◽

Ling Yang ◽

Mengmeng Tang ◽

Kai Wang ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Abscisic Acid ◽

Root Growth ◽

Primary Root ◽

Root Tip ◽

Exogenous Aba ◽

Ros Accumulation ◽

Primary Root Growth ◽

Respiratory Burst Oxidase ◽

Respiratory Burst Oxidase Homologue

Abscisic acid (ABA) is a crucial factor that affects primary root tip growth in plants. Previous research suggests that reactive oxygen species (ROS), especially hydrogen peroxide, are important regulators of ABA signalling in root growth of Arabidopsis. PROLINE-RICH EXTENSIN-LIKE RECEPTOR KINASE 4 (PERK4) plays an important role in ABA responses. Arabidopsis perk4 mutants display attenuated sensitivity to ABA, especially in primary root growth. To gain insights into the mechanism(s) of PERK4-associated ABA inhibition of root growth, in this study we investigated the involvement of ROS in this process. Normal ROS accumulation in the primary root in response to exogenous ABA treatment was not observed in perk4 mutants. PERK4 deficiency prohibits ABA-induced expression of RESPIRATORY BURST OXIDASE HOMOLOGUE (RBOH) genes, therefore the perk4-1 mutant showed decreased production of ROS in the root. The perk4-1/rbohc double mutant displayed the same phenotype as the perk4 and rbohc single mutants in response to exogenous ABA treatment. The results suggest that PERK4-stimulated ROS accumulation during ABA-regulated primary root growth may be mediated by RBOHC.

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Mechanisms for Abscisic Acid Inhibition of Primary Root Growth

Plant Signaling & Behavior ◽

10.1080/15592324.2018.1500069 ◽

2018 ◽

Vol 13 (9) ◽

pp. e1500069 ◽

Cited By ~ 16

Author(s):

Li Rong Sun ◽

Yi Bin Wang ◽

Shi Bin He ◽

Fu Shun Hao

Keyword(s):

Abscisic Acid ◽

Root Growth ◽

Primary Root ◽

Acid Inhibition ◽

Primary Root Growth

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Natural variation in primary root growth and K+ retention in roots of habanero pepper (Capsicum chinense) under salt stress

Functional Plant Biology ◽

10.1071/fp15391 ◽

2016 ◽

Vol 43 (12) ◽

pp. 1114 ◽

Cited By ~ 5

Author(s):

Emanuel Bojórquez-Quintal ◽

Nancy Ruiz-Lau ◽

Ana Velarde-Buendía ◽

Ileana Echevarría-Machado ◽

Igor Pottosin ◽

...

Keyword(s):

Salt Stress ◽

Root Growth ◽

Natural Variation ◽

Primary Root ◽

Capsicum Chinense ◽

Pharmacological Agents ◽

Habanero Pepper ◽

Nacl Concentration ◽

Primary Root Growth ◽

Chichen Itza

In this work, we analysed the natural variation in mechanisms for protection against salt stress in pepper varieties (Capsicum chinense Jacq. cv. Rex, Chichen-Itza and Naranja and Capsicum annuum L. cv. Padron), considering primary root growth and viability of the post-stressed seedlings. NaCl-induced K+ and H+ efflux in roots was also studied by ion-selective microelectrodes under application of pharmacological agents. In these pepper varieties, the magnitude of the K+ leakage in the roots positively correlated with growth inhibition of the primary root in the presence of NaCl, with Rex variety showing a higher level of tolerance than Chichen-Itza. The K+ leakage and the activity of the H+ pump in the roots were dependent on the NaCl concentration. Pharmacological analysis indicated that the NaCl-induced K+ leakage was mediated by TEA+-sensitive KOR channels but not by NSCC channels. In addition, we present evidence for the possible participation of proline, and a Na+-insensitive HAK K+ transporter expressed in habanero pepper roots for maintaining K+ homeostasis under salt stress conditions.

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