Comparative transcriptome combined with metabolomic and physiological analyses revealed ROS-mediated redox signaling affecting rice growth and cellular iron homeostasis under varying pH conditions
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Background and aims
Mechanisms by which soil pH affects rice growth await further elucidation.
We have used a Systems Biology approach to elucidate the nature of the damage caused by extreme pH to plant growth and iron homeostasis, and the adaptive plant responses elicited.
Optimum pH for rice growth was pH 6. Comparative transcriptome analysis revealed that 83% of 1318 DEGs were down-regulated at pH 4, while 73% among of 1168 DEGs were up-regulated at pH 8. GO enrichment analysis showed significant enhancement of oxidation-reduction and oxidative stress responses. Environmental pH regulated cellular oxidation-reduction processes and metabolic pathways controlling rice growth. Additionally, pH affected cellular iron-homeostasis by regulating root apoplastic iron deposition. Low pH enhanced iron mobilization from root apoplast and accumulation in plant tissues, and down-regulated iron transport related genes to prevent iron toxicity. Conversely,high pH induced blockage of iron mobilization from root apoplast. Rhizosphere pH affected aerenchyma formation and exodermis-apoplastic barriers under control of ROS, already weakened and enhanced by low pH and high pH, respectively.
ROS-mediated redox signaling plays an important role in regulating rice growth under varying pH conditions. Cellular iron homeostasis was disturbed through regulation of iron plaque formation and apoplastic iron mobilization in rice roots under acidic and alkaline conditions.
KeywordspH ROS Iron-homeostasis Exodermis-apoplastic barriers Plant growth Rice
This study was financially supported in part by the Province Key R&D Program of Hunan (2018NK1010); National Key R&D Program of China (2017YFD0200100, 2017YFD0200103); National Natural Science Foundation of China (Grant No.31101596, 31372130); Hunan Provincial Recruitment Program of Foreign Experts; and the National Oilseed Rape Production Technology System of China; “2011 Plan” supported by The Chinese Ministry of Education; Research and Innovation Project of postgraduates in Hunan province (CX2015B242), Double First-class Construction Project of Hunan Agricultural University (kxk201801005).
- Chen H, Zhang Q, Cai H, Xu F (2017). Ethylene mediates alkaline-induced rice growth inhibition by negatively regulating plasma membrane H+-ATPase activity in roots. Front Plant Sci 8: 1839Google Scholar
- Ishimaru Y, Kakei Y, Shimo H, Bashir K, Sato Y, Sato Y, Nishizawa NK (2011) A rice phenolic efflux transporter is essential for solubilizing precipitated apoplasmic iron in the plant stele. J Biol Chem 286: 24649-24655Google Scholar
- Jin CW, You GY, He YF, Tang C, Wu P, Zheng SJ (2007) Iron deficiency-induced secretion of phenolics facilitates the reutilization of root apoplastic iron in red clover. Plant Physiol 144: 278-285Google Scholar
- Koyama H, toda T, Hara T (2001) Brief exposure to low-pH stress causes irreversible damage to the growing root in Arabidopsis thaliana, pectin-ca interaction may play an important role in proton rhizotoxicity. J Exp Bot 52:361–368Google Scholar
- Li Q, Yang A, Zhang WH (2016) Efficient acquisition of iron confers greater tolerance to saline-alkaline stress in rice (Oryza sativa L.). J Exp Bot 67: 6431–6444Google Scholar
- Orman-Ligeza B, Parizot B, de Rycke R, Fernandez A, Himschoot E, Van Breusegem F (2016) RBOH-mediated ROS production facilitates lateral root emergence in Arabidopsis. Development: dev.136465Google Scholar
- Peterson CA, Perumalla CJ (1990) A survey of angiosperm species to detect hypodermal Casparian bands. II. Roots with a multiseriate hypodermis or epidermis. Boi J Linn Soc 103: 113-125Google Scholar
- Yamauchi T, Shiono K, Nagano M, Fukazawa A, Ando M, Takamure I, Mori H, Nishizawa NK, Kawai-Yamada M, Tsutsumi N, Kato K, Nakazono M (2015) Ethylene biosynthesis is promoted by very-long-chain fatty acids during ly-sigenous aerenchyma formation in rice roots. Plant Physiol 169:180–193CrossRefGoogle Scholar
- Yan F, Schubert S, Mengel K (1992) Effect of low root medium pH on net proton release, root respiration, and root growth of corn (Zea mays L.) and broad bean (Vicia faba L.). Plant Physiol 99: 415–421Google Scholar