Fungal symbiosis in rice requires an ortholog of a legume common symbiosis gene encoding a Ca2+/calmodulin-dependent protein kinase.

Department of Plant and Soil Sciences, University of Kentucky, Lexington, Kentucky 40546, USA.
Plant physiology (Impact Factor: 7.39). 01/2008; 145(4):1619-28. DOI: 10.1104/pp.107.109876
Source: PubMed

ABSTRACT In natural ecosystems, many plants are able to establish mutually beneficial symbioses with microorganisms. Of critical importance to sustainable agriculture are the symbioses formed between more than 80% of terrestrial plants and arbuscular mycorrhizal (AM) fungi and between legumes and nitrogen-fixing rhizobial bacteria. Interestingly, the two symbioses share overlapping signaling pathways in legumes, suggesting that the evolutionarily recent root nodule symbiosis may have acquired functions from the ancient AM symbiosis. The Medicago truncatula DMI3 (DOESN'T MAKE INFECTIONS3) gene (MtDMI3) and its orthologs in legumes are required for both bacterial and fungal symbioses. MtDMI3 encodes a Ca(2+)/calmodulin-dependent protein kinase (CCaMK) essential for the transduction of the Ca(2+) signal induced by the perception of Nod factors. Putative orthologs of MtDMI3 are also present in non-legumes, but their function in AM symbiosis has not been demonstrated in any non-legume species. Here, we combine reverse genetic approaches and a cross-species complementation test to characterize the function of the rice (Oryza sativa) ortholog of MtDMI3, namely, OsDMI3, in AM symbiosis. We demonstrate that OsDMI3 is not only required for AM symbiosis in rice but also is able to complement a M. truncatula dmi3 mutant, indicating an equivalent role of MtDMI3 orthologs in non-legumes.

1 Bookmark
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To understand the exceptional high grain calcium accumulation in finger millet grains, a calmodulin (CaM) gene that is strongly expressed during developing spikes of high grain calcium genotype was further characterized. Using 5'-3' RACE, the full-length CaM open reading frame (ORF) was isolated and the deduced protein sequence showed the presence of four characteristic EF motifs. Phylogenetic analysis showed that the finger millet CaM (Eleusine coracana calmodulin [EcCaM]) was identical to the rice CaM 1-1. Southern hybridization showed the presence of at least four copies of CaM gene that might be located on different regions of the finger millet "AABB" genome. Immunodetection using monospecific polyclonal anti-EcCaM antibodies revealed that EcCaM is localized in the embryo and aleurone layer and accumulates in higher amounts in high grain calcium genotype compared to the low grain calcium genotype. Furthermore, in silico analysis showed that EcCaM interacts with aquaporin which indicates that calcium is probably delivered to developing spike via mass flow of water. These results indicate that higher expression of CaM might cause greater stimulation of the downstream calcium transport machinery operative in the aleurone layer leading to the higher calcium accumulation in the grains of high grain calcium genotype.
    Applied biochemistry and biotechnology 01/2014; · 1.94 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Plants have mutualistic symbiotic relationships with rhizobia and fungi by the common symbiosis pathway, in which Ca(2+)/calmodulin-dependent protein kinase (encoded by CCaMK) is a central component. Although OsCCaMK is required for fungal accommodation in rice roots, little is known about the role of OsCCaMK in rice symbiosis with bacteria. Here, we report the effect of a Tos17-induced OsCCaMK mutant (NE1115) on CH4 flux in low-nitrogen (LN) and standard-nitrogen (SN) paddy fields as compared with wild-type (WT) Nipponbare. Growth of NE1115 was significantly decreased compared with that of WT, especially in the LN field. The CH4 flux of NE1115 in the LN field was significantly higher (156-407% in 2011 and 170-816% in 2012) than that of WT, although no difference was observed in the SN field. The copy number of pmoA (encoding methane monooxygenase in methanotrophs) was significantly higher in the roots and rhizosphere soil of WT than those of NE1115. However, mcrA (encoding methyl coenzyme M reductase in methanogens) copy number did not differ between WT and NE1115. These results were supported by a (13)C-labeled CH4-feeding experiment. In addition, the natural abundance of (15)N in WT shoots (3.05‰) was significantly lower than in NE1115 shoots (3.45‰), suggesting higher N2 fixation in WT due to dilution with atmospheric N2 (0.00‰). Thus, CH4 oxidation and N2 fixation were simultaneously activated in the root zone of WT rice in the LN field, and both processes are likely controlled by OsCCaMK.
    Applied and Environmental Microbiology 01/2014; · 3.95 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Chinese fir seedlings grow well in shrubland (including deciduous forest) soils without or less fertilizer application, but they sometimes harbor disease and show symptoms of nitrogen deficiency in ploughed (including several rotation of Chinese fir plantation) soils, where agricultural practice and clear-felling reduce the abundance and diversity of mycorrhizal fungi, and lead to destruction of mycorrhizae. Based on measurements of foliar δ15N or foliar δ15Nfol-soil in seedlings collected from 33 nurseries, we compared the effect of an AM-mediated process on nitrogen resource use between shrubland and ploughed soils. In mycorrhizal seedlings growing in shrubland soils, both foliar δ15N and foliar δ15N (fol-soil) were significantly higher than those in ploughed soils, likely because of enhanced high δ15N/NO3− absorption through AM-mediated pathways. Those results showed that foliar δ15N typically reflected the isotopic signature of the source pools of N. We suggest that the dominant N form taken up by fir seedlings growing in ploughed soils was NH4+-N rather than NO3−-N, where colonized root epidermis play an important role in exploiting soil N resource. However, the N form taken up by fir seedling growing in shrubland soils was primarily NO3−-N compared to NH4+-N, which is attributed to the high efficiency in an AM-mediated process rather than the dominance of N species in the different habitats. It is conceivable that combined colonized root epidermis with AM-mediated process may be more important than root epidermis alone in exploiting different forms of N in nursery soils. Therefore, in low N and acidic ecosystems, species other than the dominant N-NH4+, should be considered to satisfy the N demand for Chinese fir survival and growth, while the efficiency of an AM-mediated process should be determined by soil abiotic conditions.
    Pedobiologia 05/2012; 55(3):167–174. · 1.67 Impact Factor

Preview (2 Sources)