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Journal of Integrative Agriculture  2025, Vol. 24 Issue (6): 2035-2045    DOI: 10.1016/j.jia.2024.04.007
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OsEXO70L2 is required for large lateral root formation and arbuscular mycorrhiza establishment in rice
Tongming Wang1, Kai Zhou1, Bingxian Yang2, Benoit Lefebvre 1, 3#, Guanghua He1#

1 Chongqing Key Laboratory of Crop Molecular Improvement/Rice Research Institute, Academy of Agricultural Sciences, Southwest University, Chongqing 400715, China

2 College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China

3 Laboratory of Plant–Microbe–Environment Interactions (LIPME), University of Toulouse, INRAE, CNRS, Castanet-Tolosan Cedex 31326, France

 Highlights 
● Formation of large lateral roots is inhibited in Oryza sativa EXO70L2 mutant sr1.
EXO70L2 mutant in indica cultivar Jinhui 10 is unable to establish arbuscular mycorrhizal symbiosis.
● Arbuscular mycorrhizal fungi sporulation is influenced by light conditions.
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摘要  
EXO70家族蛋白是组成胞泌复合体的关键亚基,该家族的部分成员在拟南芥中被证明主要在细胞极性和形态建成过程中发挥关键作用,但EXO70蛋白在植物菌根共生方面的研究却鲜有报道。我们在水稻中鉴定了一个在进化关系上偏离EXO70家族的基因OsEXO70L2,并获得其突变体sr1和超表达株系OE-SR1。研究结果表明,OsEXO70L2参与调控水稻根系构型,不仅影响初生根的数量,而且对大侧根的形成至关重要。接种丛枝真菌后,OsEXO70L2突变体根系中丛枝真菌无法正常定殖,但可以观察到极少量的内生菌丝。我们还发现,尽管水稻根系中丛枝菌根的定殖量较低,但丛枝真菌孢子化现象仍然可以发生,并且光照周期能显著影响丛枝真菌的定殖量和孢子化位点的数量;存在护士植物时,OsEXO70L2突变体也无法被丛枝真菌正常定殖,但根内孢子的密度显著增加。结合转录组学数据,在OsEXO70L2突变体和超表达株系中,与生长素稳态相关基因的表达量受到影响,这表明OsEXO70L2可能通过调节生长素稳态影响水稻根系构型,最终影响菌根的定殖。该研究丰富了EXO70蛋白家族成员的生物学功能,为探究水稻胞泌复合体与丛枝真菌共生的关系奠定了理论基础。


Abstract  

As a major subunit of the exocyst complex, members of the EXO70 family have mainly been shown to play roles in cell polarity and morphogenesis in Arabidopsis, but their roles in plant endosymbiosis, such as with arbuscular mycorrhizal fungi (AMF), have rarely been reported.  Here, using knockout and overexpression lines, we show that OsEXO70L2, which encodes a divergent EXO70 protein in rice, controls the number of primary roots and is essential for large lateral root formation.  Furthermore, the OsEXO70L2 mutant sr1 displayed rare internal AMF hyphae and no arbuscules.  We also found that AMF sporulation can occur in roots despite low colonization and that AMF colonization and sporulation are modulated by photoperiod and co-culture with clover.  Finally, genes related to auxin homeostasis were found to be affected in the OsEXO70L2 knockout or overexpression lines, suggesting that auxin is at least partly responsible for the phenotypes.  This study provides new perspectives on the role of the exocyst complex during root development and AM in rice.

Keywords:  rice        EXO70        root formation        arbuscular mycorrhizal        sporulation  
Received: 16 January 2024   Accepted: 11 March 2024 Online: 10 April 2024  
Fund: 
This work was supported by the National Natural Science Foundation of China (32171970), the Chongqing Talent Program, China (cstc2022ycjh-bgzxm0073), the Natural Science Foundation of Chongqing, China (cstc2021jcyj-cxttX0004), and the Rice Innovative Research Team of Chongqing Modern Agricultural Industrial Technology System, China (CQMAITS202301). 
About author:  #Correspondence Guanghua He, Tel/Fax: +86-23-68250158, E-mail: heghswu@163.com; Benoit Lefebvre, Tel/Fax: +33-5-61285322, E-mail: benoit.lefebvre@inrae.fr

Cite this article: 

Tongming Wang, Kai Zhou, Bingxian Yang, Benoit Lefebvre, Guanghua He. 2025. OsEXO70L2 is required for large lateral root formation and arbuscular mycorrhiza establishment in rice. Journal of Integrative Agriculture, 24(6): 2035-2045.

Anders S. 2010. Analysing RNA-Seq data with the DESeq package. Molecular Biology43, 1–17.

Boyd C, Hughes T, Pypaert M, Novick P. 2004. Vesicles carry most exocyst subunits to exocytic sites marked by the remaining two subunits, Sec3p and Exo70p. Journal of Cell Biology167, 889–901.

Buendia L, Ribeyre C, Bensmihen S, Lefebvre B. 2019. Brachypodium distachyon tar2lhypo mutant shows reduced root developmental response to symbiotic signal but increased arbuscular mycorrhiza. Plant Signaling & Behavior14, e1651608.

Buysens C, de Boulois H D, Declerck S. 2015. Do fungicides used to control Rhizoctonia solani impact the non-target arbuscular mycorrhizal fungus Rhizophagus irregularisMycorrhiza25, 277–288.

Chen C H, Liu M L, Jiang L, Liu X F, Zhao J Y, Yan S S, Yang S, Ren H Z, Liu R Y, Zhang X L. 2014. Transcriptome profiling reveals roles of meristem regulators and polarity genes during fruit trichome development in cucumber (Cucumis sativus L.). Journal of Experimental Botany65, 4943–4958.

Cole R A, McInally S A, Fowler J E. 2014. Developmentally distinct activities of the exocyst enable rapid cell elongation and determine meristem size during primary root growth in ArabidopsisBMC Plant Biology14, 1–20.

Cui L, Wang J G, Tang Z H, Zhang Z, Yang S, Guo F, Li X G, Meng J J, Zhang J L, Kuzyakov Y, Wan S B. 2024. General and specialized metabolites in peanut roots regulate arbuscular mycorrhizal symbiosis. Journal of Integrative Agriculture23, 2618–2632.

Cvrcková F, Grunt M, Bezvoda R, Hála M, Kulich I, Rawat A, Zársky V. 2012. Evolution of the land plant exocyst complexes. Frontiers in Plant Science3, 159.

Dai H L, Zhang X W, Zhao B Y, Shi J C, Zhang C, Wang G, Yu N, Wang E T. 2022. Colonization of mutualistic mycorrhizal and parasitic blast fungi requires OsRAM2-regulated fatty acid biosynthesis in rice. Molecular Plant-Microbe Interactions35, 178–186.

Drdová E J, Synek L, Pecenková T, Hála M, Kulich I, Fowler J E, Murphy A S, Zarsky V. 2013. The exocyst complex contributes to PIN auxin efflux carrier recycling and polar auxin transport in ArabidopsisPlant Journal73, 709–719.

Etemadi M, Gutjahr C, Couzigou J M, Zouine M, Lauressergues D, Timmers A, Audran C, Bouzayen M, Bécard G, Combier J P. 2014. Auxin perception is required for arbuscule development in arbuscular mycorrhizal symbiosis. Plant Physiology166, 281–292.

Feddermann N, Muni R R D, Zeier T, Stuurman J, Ercolin F, Schorderet M, Reinhardt D. 2010. The PAM1 gene of petunia, required for intracellular accommodation and morphogenesis of arbuscular mycorrhizal fungi, encodes a homologue of VAPYRIN. Plant Journal64, 470–481.

Guo R, Wu Y N, Liu C C, Liu Y N, Tian L, Cheng J F, Pan Z Y, Wang D, Wang B. 2022. OsADK1, a novel kinase regulating arbuscular mycorrhizal symbiosis in rice. New Phytologist234, 256–268.

Gutjahr C, Banba M, Croset V, An K, Miyao A, An G, Hirochika H, Imaizumi-Anraku H, Paszkowski U. 2008. Arbuscular mycorrhiza-specific signaling in rice transcends the common symbiosis signaling pathway. Plant Cell20, 2989–3005.

Gutjahr C, Casieri L, Paszkowski U. 2009. Glomus intraradices induces changes in root system architecture of rice independently of common symbiosis signaling. New Phytologist182, 829–837.

Hála M, Cole R, Synek L, Drdová E, Pecenková T, Nordheim A, Lamkemeyer T, Madlung J, Hochholdinger F, Fowler J E, Zársky V. 2008. An exocyst complex functions in plant cell growth in Arabidopsis and tobacco. Plant Cell20, 1330–1345.

He B, Guo W. 2009. The exocyst complex in polarized exocytosis. Current Opinion in Cell Biology21, 537–542.

He B, Xi F G, Zhang X Y, Zhang J, Guo W. 2007. Exo70 interacts with phospholipids and mediates the targeting of the exocyst to the plasma membrane. EMBO Journal26, 4053–4065.

Hiei Y, Komari T. 2008. Agrobacterium-mediated transformation of rice using immature embryos or calli induced from mature seed. Nature Protocols3, 824–834.

Hochholdinger F, Park W J, Sauer M, Woll K. 2004. From weeds to crops: Genetic analysis of root development in cereals. Trends in Plant Science9, 42–48.

Hou H N, Fang J B, Liang J H, Diao Z J, Wang W, Yang D W, Li S P, Tang D Z. 2020. OsExo70B1 positively regulates disease resistance to Magnaporthe oryzae in rice. International Journal of Molecular Sciences21, 7049.

Kulich I, Cole R, Drdová E, Cvrcková F, Soukup A, Fowler J, Zársky V. 2010. Arabidopsis exocyst subunits and exocyst interactor are involved in the localized deposition of seed coat pectin. New Phytologist188, 615–625.

Kulich I, Vojtíková Z, Glanc M, Ortmannová J, Rasmann S, Zársky V. 2015. Cell wall maturation of Arabidopsis trichomes is dependent on exocyst subunit EXO70H4 and involves callose deposition. Plant Physiology168, 120–131.

Li S P, Chen M, Yu D L, Ren S C, Sun S F, Liu L D, Ketelaar T, Emons A M C, Liu C M. 2013. EXO70A1-mediated vesicle trafficking is critical for tracheary element development in ArabidopsisPlant Cell25, 1774–1786.

Liao Q, Shen J, Liu J F, Sun X, Zhao G G, Chang Y Z, Xu L T, Li X R, Zhao Y, Zheng H Q, Zhao Y, Wu Z D. 2014. Genome-wide identification and functional annotation of long noncoding RNAs from RNA-seq data. Parasitology Research113, 1269–1281.

Liu C C, Liu Y N, Cheng J F, Guo R, Tian L, Wang B. 2022. Dual roles of OsGH3.2 in modulating rice root morphology and affecting arbuscular mycorrhizal symbiosis. Frontiers in Plant Science13, 853435.

Liu C W, Breakspear A, Stacey N, Findlay K, Nakashima J, Ramakrishnan K, Liu M X, Xie F, Endre G, de Carvalho-Niebel F, Oldroyd G E D, Udvardi M K, Fournier J, Murray J D. 2019. A protein complex required for polar growth of rhizobial infection threads. Nature Communications10, 2848.

Love M I, Huber W, Anders S. 2014. Moderated estimation of fold change and dispersion for RNA-seq data with DESeq2. Genome Biology15, 11–21.

Markovic V, Cvrcková F, Potocky M, Kulich I, Pejchar P, Kollárová E, Synek L, Zársky V. 2020. EXO70A2 is critical for exocyst complex function in pollen development. Plant Physiology184, 1823–1839.

Mortazavi A, Williams B A, Mccue K, Schaeffer L, Wold B. 2008. Mapping and quantifying mammalian transcriptomes by RNA-Seq. Nature Methods5, 621–628.

Ogura T, Goeschl C, Filiault D, Mirea M, Slovak R, Wolhrab B, Satbhai S B, Busch W. 2019. Root system depth in Arabidopsis is shaped by via the dynamic modulation of auxin transport. Cell178, 400–413.

Pecenková T, Hála M, Kulich I, Kocourková D, Drdová E, Fendrych M, Toupalová H, Zársky V. 2011. The role for the exocyst complex subunits Exo70B2 and Exo70H1 in the plant–pathogen interaction. Journal of Experimental Botany62, 2107–2116.

Rebouillat J, Dievart A, Verdeil J L, Escoute J, Giese G, Breitler J C, Gantet P, Espeout S, Guiderdoni E, Périn C. 2009. Molecular genetics of rice root development. Rice2, 15–34.

Redkar A, Sabale M, Zuccaro A, Di Pietro A. 2022. Determinants of endophytic and pathogenic lifestyle in root colonizing fungi. Current Opinion in Plant Biology67, 102226.

Robinson M D, Oshlack A. 2010. A scaling normalization method for differential expression analysis of RNA-seq data. Genome Biology11, 1–9.

Roth R, Chiapello M, Montero H, Gehrig P, Grossmann J, O’Holleran K, Hartken D, Walters F, Yang S Y, Hillmer S, Schumacher K, Bowden S, Craze M, Wallington E J, Miyao A, Sawers R, Martinoia E, Paszkowski U. 2018. A rice Serine/Threonine receptor-like kinase regulates arbuscular mycorrhizal symbiosis at the peri-arbuscular membrane. Nature Communications9, 4677.

Safavian D, Zayed Y, Indriolo E, Chapman L, Ahmed A, Goring D R. 2015. RNA silencing of exocyst genes in the stigma impairs the acceptance of compatible pollen in ArabidopsisPlant Physiology169, 2526–2538.

Stegmann M, Anderson R G, Ichimura K, Pecenkova T, Reuter P, Žárský V, McDowell J M, Shirasu K, Trujillo M. 2012. The ubiquitin ligase PUB22 targets a subunit of the exocyst complex required for PAMP-triggered responses in ArabidopsisThe Plant Cell24, 4703–4716.

Su Y Y, Qi Y L, Cai L. 2012. Induction of sporulation in plant pathogenic fungi. Mycology3, 195–200.

Synek L, Pleskot R, Sekeres J, Serrano N, Vukasinovic N, Ortmannová J, Klejchová M, Pejchar P, Batystová K, Gutkowska M, Janková-Drdová E, Markovic V, Pecenkova T, Santrucek J, Zársky V, Potocky M. 2021. Plasma membrane phospholipid signature recruits the plant exocyst complex via the EX070A1 subunit. Proceedings of the National Academy of Sciences of the United States of America118, e2105287118.

Synek L, Schlager N, Eliás M, Quentin M, Hauser M T, Zársky V. 2006. AtEXO70A1, a member of a family of putative exocyst subunits specifically expanded in land plants, is important for polar growth and plant development. Plant Journal48, 54–72.

Synek L, Vukasinovic N, Kulich I, Hála M, Aldorfová K, Fendrych M, Zársky V. 2017. EXO70C2 is a key regulatory factor for optimal tip growth of pollen. Plant Physiology174, 223–240.

Tan X Y, Feng Y H, Liu Y L, Bao Y Q. 2016. Mutations in exocyst complex subunit gene impaired polar auxin transport and PIN protein recycling in primary root. Plant Science250, 97–104.

Vukasinovic N, Oda Y, Pejchar P, Synek L, Pecenková T, Rawat A, Sekeres J, Potocky M, Zársky V. 2017. Microtubule-dependent targeting of the exocyst complex is necessary for xylem development in ArabidopsisNew Phytologist213, 1052–1067.

Wang L, Ge T T, Peng H T, Wang C, Liu T K, Hou X L. 2013. Molecular cloning, expression analysis and localization of Exo70A1 related to self incompatibility in non-heading Chinese cabbage (Brassica campestris ssp. chinensis). Journal of Integrative Agriculture12, 2149–2156.

Wang M, Chen C, Xu Y Y, Jiang R X, Han Y, Xu Z H, Chong K. 2004. A practical vector for efficient knockdown of gene expression in rice (Oryza sativa L.). Plant Molecular Biology Reporter22, 409–417.

Wang W, Liu N, Gao C Y, Cai H R, Romeis T, Tang D Z. 2020. The Arabidopsis exocyst subunits EXO70B1 and EXO70B2 regulate FLS2 homeostasis at the plasma membrane. New Phytologist227, 529–544.

Xing Y D, Wang N, Zhang T Q, Zhang Q L, Du D, Chen X L, Lu X, Zhang Y Y, Zhu M D, Liu M M, Sang X C, Li Y F, Ling Y H, He G H. 2021. SHORT-ROOT 1 is critical to cell division and tracheary element development in rice roots. Plant Journal105, 1179–1191.

Yu G C, Wang L G, Han Y Y, He Q Y. 2012. clusterProfiler: An R package for comparing biological themes among gene clusters. Omics - A Journal of Integrative Biology16, 284–287.

Zhang X C, Pumplin N, Ivanov S, Harrison M J. 2015. EXO70I is required for development of a sub-domain of the periarbuscular membrane during arbuscular mycorrhizal symbiosis. Current Biology25, 2189–2195.

Zhao T, Rui L, Li J, Nishimura M T, Vogel J P, Liu N, Liu S M, Zhao Y F, Dangl J L, Tang D Z. 2015. A truncated NLR protein, TIR-NBS2, is required for activated defense responses in the exo70B1 mutant. PLoS Genetics11, e1004945.

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