Diversity of culturable methylotrophic bacteria in different genotypes of groundnut and their potential for plant growth promotion
This study aimed at documenting the culturable methylotrophic bacterial diversity across different groundnut genotypes and evaluating their effect on the growth of groundnut. 80 methylotrophic bacterial isolates were obtained from the phyllosphere of 15 groundnut genotypes collected from Tamil Nadu, India. The bacterial isolates were identified through sequencing of the 16S rDNA and were tested for their plant growth-promoting properties. Groundnut seeds were inoculated with methylotrophic bacteria and their effect on growth was evaluated via in vitro and pot experiments. Molecular identification revealed that the isolates belonged to 30 different species. A higher diversity of methylotrophic bacteria at genus and species level was found in groundnut genotype TMV2. Shannon diversity index was the highest in genotype TMV7, followed by VRI2 and TMV2. Similarly, geographical location also influenced the diversity of methylotrophic bacteria. In vitro seed germination assay revealed that methylotrophic isolates enhanced root growth and improved formation of root hair. The radicle length of treated seeds ranged from 2.7 to 8.4 cm. A higher shoot length was observed in the plants from seeds treated with Methylobacterium radiotolerans VRI8-A4 (27.3 cm), followed by Pseudomonas psychrotolerans TMV13-A1 (26.3 cm) and Bacillus aryabhattai K-CO3-3 (23 cm). The findings of this study strongly suggest that beneficial methylotrophic bacteria associated with the phyllosphere of groundnut play a major role in regulating plant growth.
KeywordsGroundnut Phyllosphere Methylotrophic bacteria Plant growth-promoting traits
This study was supported by the Science and Engineering Research Board (SERB), Department of Science and Technology (DST), under Grant No. PDF/2015/000456.
Compliance with ethical standards
Conflict of interest
The authors declare that we have no competing interests.
- Abanda-Nkpwatt D, Musch M, Tschiersch J, Boettner M, Schwab W (2006) Molecular interaction between Methylobacterium extorquens and seedlings: growth promotion, methanol consumption, and localization of the methanol emission site. J Exp Bot 57:4025–4032. https://doi.org/10.1093/jxb/erl173 CrossRefGoogle Scholar
- Anandham R, Choi KH, Indira Gandhi P, Yim WJ, Park SJ, Kim KA, Madhaiyan M, Sa TM (2007) Evaluation of shelf life and rock phosphate solubilization of Burkholderia sp. in nutrient-amended clay, rice bran and rock phosphate-based granular formulation. World J Microbiol Biotechnol 23:1121–1129. https://doi.org/10.1007/s11274-006-9342-y CrossRefGoogle Scholar
- Bric JM, Bostock RM, Silverstone SE (1991) Rapid in situ assay for indoleacetic-acid production by bacteria immobilized on a nitrocellulose membrane. Appl Environ Microb 57:535–538Google Scholar
- Hubbard A, Lewis CM, Yoshida K, Ramirez-Gonzalez RH, de Vallavieille-Pope C, Thomas J, Kamoun S, Bayles R, Uauy C, Saunders DG (2015) Field pathogenomics reveals the emergence of a diverse wheat yellow rust population. Genome Biol 16:23. https://doi.org/10.1186/s13059-015-0590-8 CrossRefGoogle Scholar
- Maciel JL, Ceresini PC, Castroagudin VL, Zala M, Kema GH, McDonald BA (2014) Population structure and pathotype diversity of the wheat blast pathogen Magnaporthe oryzae 25 years after its emergence in Brazil. Phytopathology 104:95–107. https://doi.org/10.1094/PHYTO-11-12-0294-R CrossRefGoogle Scholar
- Meena KK, Kumar M, Kalyuzhnaya MG, Yandigeri MS, Singh DP, Saxena AK, Arora DK (2012) Epiphytic pink-pigmented methylotrophic bacteria enhance germination and seedling growth of wheat (Triticum aestivum) by producing phytohormones. Antonie Leeuwenhoek 101:777–786. https://doi.org/10.1007/s10482-011-9692-9 CrossRefGoogle Scholar
- Morris CE, Monier JM, Jacques MA (1997) Methods for observing microbial biofilms directly on leaf surfaces and recovering them for isolation of culturable microorganisms. Appl Environ Microbiol 63:1570–1576Google Scholar
- Pfeiffer S, Mitter B, Oswald A, Schloter-Hai B, Schloter M, Declerck S, Sessitsch A (2017) Rhizosphere microbiomes of potato cultivated in the high andes show stable and dynamic core microbiomes with different responses to plant development. FEMS Microbiol Ecol 93:242. https://doi.org/10.1093/femsec/fiw242 CrossRefGoogle Scholar
- Ryu JH, Madhaiyan M, Poonguzhali S, Yim WJ, Indiragandhi P, Kim KA, Anandham R, Yun JC, Kim KH, Sa TM (2006) Plant growth substances produced by Methylobacterium spp. and Their effect on tomato (Lycopersicon esculentum L.) and red pepper (Capsicum annuum L.) growth. J Microbiol Biotechnol 16:1622–1628Google Scholar
- Sharma KL, Ramakrishna YS, Samra JS, Sharma KD, Mandal UK, Venkateswarlu B, Korwar GR, Srinivas K (2009) Strategies for improving the productivity of rainfed farms in india with special emphasis on soil quality improvement. J Crop Impro 23:430–450. https://doi.org/10.1080/15427520903013431 CrossRefGoogle Scholar
- Sy A, Timmers AC, Knief C, Vorholt JA (2005) Methylotrophic metabolism is advantageous for Methylobacterium extorquens during colonization of Medicago truncatula under competitive conditions. Appl Environ Microbiol 71:7245–7252. https://doi.org/10.1128/AEM.71.11.7245-7252.2005 CrossRefGoogle Scholar
- Tani A, Sahin N, Fujitani Y, Kato A, Sato K, Kimbara K (2015) Methylobacterium species promoting rice and barley growth and interaction specificity revealed with whole-cell matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF/MS) analysis. PLoS One 10:e0129509. https://doi.org/10.1371/journal.pone.0129509 CrossRefGoogle Scholar
- Valverde A, Tirante MG, Sierra MM, Rivas R, Santa-Regina I, Igual JM (2017) Culturable bacterial diversity from the chestnut (Castanea sativa Mill.) phyllosphere and antagonism against the fungi causing the chestnut blight and ink diseases. AIMS Microbiol 3:293–314. https://doi.org/10.3934/microbiol.2017.2.293 CrossRefGoogle Scholar