CML9, a multifunctionalArabidopsis thalianacalmodulin-like protein involved in stress responses and plant growth?

Abstract

Many stimuli such as hormones and stress factors elicit changes in intracellular calcium content that serve to convey information and activate appropriate responses. 1 These Ca 2+ signals are perceived by different Ca 2+ sensors, and calmodulin (CaM) is one of the best characterized Ca 2+ sensors in eukaryotes. Calmodulinlike (CML) proteins extend the Ca 2+ -toolkit in plants; CMLs share sequence similarity with the ubiquitous and highly conserved CaM, however, except for some of them, their roles at physiological and molecular levels remain largely unknown. 2,3In our group, we reported data on Arabidopsis thaliana CML9 that exhibits 46% amino acid sequence identity with CaM. 4,5 We showed that CML9 transcripts are found in all organs and that CML9 gene is rapidly induced by both abiotic and biotic stress. In a recent publication in Plant Journal, we demonstrated that CML9 expression is also rapidly induced by the phytopathogenic bacteria Pseudomonas syringae pv tomato DC3000 (Pst DC3000) 4 and that this upregulation belongs to salicylic acid (SA) production and to the flagellin perception receptor FLS2. Moreover, exogenous applications of SA or flg22, the biological active peptide of flagellin, are also able to induce rapid and transient CML9 gene expression and using a reverse genetic approach, we established that CML9 participates in plant innate immunity through a flagellin-dependent signaling pathway. 4 In addition to mediate plant innate immunity, flagellin and flg22 are also known to inhibit root elongation and seedling growth.6 Thus, we explored this facet of flagellin effect and we bring here new informations on plant growth behavior of CML9 overexpressing and knockout lines upon flg22 treatments and Plants have evolved complex signaling networks to respond to their fluctuating environment and adapt their growth and development. Calcium-dependent signaling pathways play key role in the onset of these adaptive responses. in plant cells, the intracellular calcium transients are triggered by numerous stimuli and it is supposed that the large repertory of calcium sensors present in higher plants could contribute to integrate these signals in physiological responses. here, we present data on CmL9, a calmodulin-like protein that appears to be involved in plant responses to both biotic and abiotic stress. using a reverse genetic approach based on gain and loss of function mutants, we present here data indicating that this CmL might also be involved in root growth control in response to the flagellin, a pathogen-associated molecular pattern (PamP) also involved in plant immunity. Keywords: Calmodulin-like protein, Arabidopsis thaliana, root growth, flagellin, gibberellins discuss the possible involvement of CML9 in plant growth control through hormonal compounds. CML9, a multifunctional The cml9 Genotypes Exhibit Altered Responses to FlagellinAs previously showed, cml9 mutants or CML9 overexpressors exhibit respectively an enhanced susceptibility and a better resistance against phytopathogenic bacteria. 4 Using...

A calmodulin‐like protein regulates plasmodesmal closure during bacterial immune responses

“…S6). This contrasts the action of CML9 in the nucleus, which appears to negatively regulate PR1 expression and the deposition of callose during flg22 responses (Leba et al ., 2012). As the same transcriptional responses of these known early innate immunity induced genes are activated in wildtype, CML41 overexpression and knockdown plants, this is strong evidence that CML41 does not work upstream of any of the corresponding response pathways.…”

The Role of Calmodulin and Related Proteins in Plant Cell Function: An Ever-Thickening Plot

“…signaling in plants, and in recent years it has become increasingly clear that CaM and CML Ca 2? sensor proteins play pivotal roles in NO production and plant defense signaling [86,112,113,116,175], as well as an ever-growing number of plant processes including developmental transitions, autophagy, and exposure to environmental stresses [75,91,102,149,175,184,189,190,194].…”

Calmodulin-Like (CML) Gene Family in Medicago truncatula: Genome-Wide Identification, Characterization and Expression Analysis

“…Calcium is a universal second messenger in mediating adaptation responses of plants to abiotic and biotic stresses [ 1 ]. Diverse stimuli such as plant hormones, low temperature, drought, salt, and pathogens induce rapid and transient changes in cellular Ca 2+ concentration [ 2 ], which are sensed and decoded by calcium-binding proteins (CBP) to activate downstream reactions [ 3 ]. The CBPs include calmodulins (CaMs), CaM-like proteins (CMLs), Ca 2+ -dependent protein kinases (CPKs/CDPKs) and calcineurin B-like proteins (CBLs) in plants [ 4 , 5 , 6 ].…”

“…The other CMLs, such as CML12, CML25, CML38, CML39 and CML43, are involved in plant growth and development [ 25 , 26 , 27 , 28 , 29 ]. CML8, CML41, CML42, CML46 and CML47 are involved in plant resistance to bacterium pathogens [ 30 , 31 , 32 , 33 ], while CML9 , CML24 , CML37 , CML38 , and CML39 transcripts are induced by salt or/and drought stress [ 2 , 23 , 34 , 35 ]. CML20 is a negative regulator, while CML24 and CML37 are positive regulators in ABA-signaling during drought stress [ 23 , 34 , 36 ].…”