An experimental system to study responses of Medicago truncatula roots to chitin oligomers of high degree of polymerization and other microbial elicitors
- 969 Downloads
A fully acetylated, soluble CO preparation of mean DP of ca. 7 was perceived with high sensitivity by M. truncatula in a newly designed versatile root elicitation assay.
The root system of legume plants interacts with a large variety of microorganisms, either pathogenic or symbiotic. Understanding how legumes recognize and respond specifically to pathogen-associated or symbiotic signals requires the development of standardized bioassays using well-defined preparations of the corresponding signals. Here we describe the preparation of chitin oligosaccharide (CO) fractions from commercial chitin and their characterization by a combination of liquid-state and solid-state nuclear magnetic resonance spectroscopy. We show that the CO fraction with highest degree of polymerization (DP) became essentially insoluble after lyophilization. However, a fully soluble, fully acetylated fraction with a mean DP of ca. 7 was recovered and validated by showing its CERK1-dependent activity in Arabidopsis thaliana. In parallel, we developed a versatile root elicitation bioassay in the model legume Medicago truncatula, using a hydroponic culture system and the Phytophthora β-glucan elicitor as a control elicitor. We then showed that M. truncatula responded with high sensitivity to the CO elicitor, which caused the production of extracellular reactive oxygen species and the transient induction of a variety of defense-associated genes. In addition, the bioassay allowed detection of elicitor activity in culture filtrates of the oomycete Aphanomyces euteiches, opening the way to the analysis of recognition of this important legume root pathogen by M. truncatula.
KeywordsChitooligosaccharide Nuclear magnetic resonance Reactive oxygen species Defense gene activation Aphanomyces
We thank Dr. S. Bensmihen (LIPM, UMR CNRS-INRA 2594/441, Toulouse) for supplying seeds of the A. thaliana cerk1 GABI-KAT mutant 096F09, and Dr. H. Chanzy (CERMAV-CNRS, Grenoble) and J.J. Bono (LIPM, UMR CNRS-INRA 2594/441, Toulouse) for continuous support. This work was funded by the Région Midi-Pyrénées, the CNRS (PhD Grant INEE 36 to A.N.), and the French Agence Nationale de la Recherche (ANR-08-BLAN-0208-01 “Sympasignal”).
- Badreddine I, Lafitte C, Heux L, Skandalis N, Spanou Z, Martinez Y, Esquerré-Tugayé MT, Bulone V, Dumas B, Bottin A (2008) Cell wall chitosaccharides are essential components and exposed patterns of the phytopathogenic oomycete Aphanomyces euteiches. Eukaryot Cell 7:1980–1993PubMedCrossRefGoogle Scholar
- Djébali N, Jauneau A, Ameline-Torregrosa C, Chardon F, Jaulneau V, Mathé C, Bottin A, Cazaux M, Pilet-Nayel M-L, Baranger A, Aouani ME, Esquerré-Tugayé M-T, Dumas B, Huguet T, Jacquet C (2009) Partial resistance of Medicago truncatula to Aphanomyces euteiches is associated with protection of the root stele and is controlled by a major QTL rich in proteasome-related genes. Mol Plant Microbe Interact 22:1043–1055PubMedCrossRefGoogle Scholar
- Hruz T, Laule O, Szabo G, Wessendorp F, Bleuler S, Oertle L, Widmayer P, Gruissem W, Zimmermann P (2008) Genevestigator v3: a reference expression database for the meta-analysis of transcriptomes. Adv Bioinforma 2008:420747Google Scholar
- Nakagawa T, Kaku H, Shimoda Y, Sugiyama A, Shimamura M, Takanashi K, Yazaki K, Aoki T, Shibuya N, Kouchi H (2011) From defense to symbiosis: limited alterations in the kinase domain of LysM receptor-like kinases are crucial for evolution of legume-Rhizobium symbiosis. Plant J 65:169–180PubMedCrossRefGoogle Scholar
- Shahidi F, Abuzaytoun R (2005) Chitin, chitosan, and co-products: chemistry, production, applications, and health effects. In: Advances in food and nutrition research, vol 49. Academic Press, San Diego, pp 93–135Google Scholar
- Uppalapati SR, Marek SM, Lee HK, Nakashima J, Tang Y, Sledge MK, Dixon RA, Mysore KS (2009) Global gene expression profiling during Medicago truncatula-Phymatotrichopsis omnivora interaction reveals a role for jasmonic acid, ethylene, and the flavonoid pathway in disease development. Mol Plant Microbe Interact 22:7–17PubMedCrossRefGoogle Scholar
- Vailleau F, Sartorel E, Jardinaud MF, Chardon F, Genin S, Huguet T, Gentzbittel L, Petitprez M (2007) Characterization of the interaction between the bacterial wilt pathogen Ralstonia solanacearum and the model legume plant Medicago truncatula. Mol Plant Microbe Interact 20:159–167PubMedCrossRefGoogle Scholar
- Young ND, Debellé F, Oldroyd GE, Geurts R, Cannon SB, Udvardi MK, Benedito VA, Mayer KF, Gouzy J, Schoof H, Van de Peer Y, Proost S, Cook DR, Meyers BC, Spannagl M, Cheung F, De Mita S, Krishnakumar V, Gundlach H, Zhou S, Mudge J, Bharti AK, Murray JD, Naoumkina MA, Rosen B, Silverstein KA, Tang H, Rombauts S, Zhao PX, Zhou P, Barbe V, Bardou P, Bechner M, Bellec A, Berger A, Bergès H, Bidwell S, Bisseling T, Choisne N, Couloux A, Denny R, Deshpande S, Dai X, Doyle JJ, Dudez AM, Farmer AD, Fouteau S, Franken C, Gibelin C, Gish J, Goldstein S, González AJ, Green PJ, Hallab A, Hartog M, Hua A, Humphray SJ, Jeong DH, Jing Y, Jöcker A, Kenton SM, Kim DJ, Klee K, Lai H, Lang C, Lin S, Macmil SL, Magdelenat G, Matthews L, McCorrison J, Monaghan EL, Mun JH, Najar FZ, Nicholson C, Noirot C, O’Bleness M, Paule CR, Poulain J, Prion F, Qin B, Qu C, Retzel EF, Riddle C, Sallet E, Samain S, Samson N, Sanders I, Saurat O, Scarpelli C, Schiex T, Segurens B, Severin AJ, Sherrier DJ, Shi R, Sims S, Singer SR, Sinharoy S, Sterck L, Viollet A, Wang BB, Wang K, Wang M, Wang X, Warfsmann J, Weissenbach J, White DD, White JD, Wiley GB, Wincker P, Xing Y, Yang L, Yao Z, Ying F, Zhai J, Zhou L, Zuber A, Dénarié J, Dixon RA, May GD, Schwartz DC, Rogers J, Quétier F, Town CD, Roe BA (2011) The Medicago genome provides insight into the evolution of rhizobial symbioses. Nature 480:520–524PubMedCrossRefGoogle Scholar