Abstract
Azospirillum brasilense is a plant growth-promoting bacterium that is utilized as a bio-fertilizer worldwide. Inoculation of crops with A. brasilense can lead to a substantial boost in crop yield, although this enhancement is variable. Sometimes crop production is enhanced as much as 70% and other times enhancement does not occur at all. To solve this problem, a greater understanding of A. brasilense – plant interactions is needed. While the root/rhizosphere ecology of A. brasilense has been studied extensively there are no significant studies that address whether A. brasilense populates above ground plant tissues. In this study, we use a combination of qPCR, transcriptomics, confocal microscopy, and culturing techniques to map the in-planta distribution of a GFP-expressing A. brasilense in Phaseolus vulgaris (common bush bean). We show that A. brasilense constitute part of the plant bacterial microflora well above the root system. During P. vulgaris development A. brasilense was shown to actively move to developing bean seeds where it forms a significant intercellular population. GFP-expressing A. brasilense was shown to vertically transmit to successive plant generations demonstrating that A. brasilense in the seed constitute an effective inoculum. The ability of A. brasilense to not only colonize roots but to also actively migrate to developing seeds indicates the existence of a more complex symbiotic relationship than previously understood.
![](http://media.springernature.com/m312/springer-static/image/art%3A10.1007%2Fs13199-018-0539-2/MediaObjects/13199_2018_539_Fig1_HTML.gif)
![](http://media.springernature.com/m312/springer-static/image/art%3A10.1007%2Fs13199-018-0539-2/MediaObjects/13199_2018_539_Fig2_HTML.gif)
![](http://media.springernature.com/m312/springer-static/image/art%3A10.1007%2Fs13199-018-0539-2/MediaObjects/13199_2018_539_Fig3_HTML.gif)
![](http://media.springernature.com/m312/springer-static/image/art%3A10.1007%2Fs13199-018-0539-2/MediaObjects/13199_2018_539_Fig4_HTML.gif)
![](http://media.springernature.com/m312/springer-static/image/art%3A10.1007%2Fs13199-018-0539-2/MediaObjects/13199_2018_539_Fig5_HTML.gif)
![](http://media.springernature.com/m312/springer-static/image/art%3A10.1007%2Fs13199-018-0539-2/MediaObjects/13199_2018_539_Fig6_HTML.gif)
![](http://media.springernature.com/m312/springer-static/image/art%3A10.1007%2Fs13199-018-0539-2/MediaObjects/13199_2018_539_Fig7_HTML.gif)
![](http://media.springernature.com/m312/springer-static/image/art%3A10.1007%2Fs13199-018-0539-2/MediaObjects/13199_2018_539_Fig8_HTML.gif)
Similar content being viewed by others
References
Agera S, Igber G, Ammonium J (2012) Use of bio fertilizers for soil fertility restoration, weeds and pest control in forest management. Niger J Educ Health Tech Res 3:20–26
Alexandre G, Greer SE, Zhulin IB (2000) Energy taxis is the dominant behavior in Azospirillum brasilense. J Bact 182:6042–6048
Bashan Y, Bustillos JJ, Leyva LA, Hernandez JP, Bacilio M (2006) Increase in auxiliary photo protective photosynthetic pigments in wheat seedlings induced by Azospirillum brasilense. Bio Biofert Soil 42:279–283
Bashan Y, de Bashan LE (2010) How the plant growth promoting bacterium Azospirillum promotes plant growth – a critical assessment. Adv Agron 108:77–137
Bashan Y, de Bashan LE (2002) Protection of tomato seedlings against infection by Pseudomonas syringae pv. Tomato by using the plant growth-promoting bacterium Azospirillum brasilense. Appl Environ Microbiol 68:2637–2643
Bashan Y, Holguin G, de Bashan LE (2004) Azospirillum-plant relationships: physiological, molecular, agricultural, and environmental advances (1997-2003). Can J Microbiol 50:521–577
Bashan Y, Holguin G (1994) Root to root travel of the beneficial bacterium Azospirillum brasilense. Appl Environ Microbiol 60:2120–2131
Bashan Y, Puente ME, Rodriguez-Mendosa MN, Toledo G, Holguin G, Ferrere-Cerrato R, Pedrin S (1995) Survival of Azospirillum in bulk soil and rhizosphere of 23 soil types. Appl Environ Microbiol 61:1938–1945
Bashan Y (1986) Enhancement of wheat root colonization and plant development by Azospirillum brasilense Cd following temporary depression of rhizosphere microflora. Appl Environ Microbiol 51:1067–1071
Bashan Y (1986b) Synthetic inoculant carriers for slow release of bacteria that affect plant growth. Appl Environ Microbiol 51:1089–1098
Bhardwaj D, Ansari MW, Shaoo RK, Tuteja N (2014) Bio fertilizer function as key player in sustainable agriculture by improving soil fertility, plant tolerance and crop productivity. Microb Cell Factories 13:66–76
Bragina A, Cardinale M, Berg C, Berg G (2013) Vertical transmission explains the specific Burkholderia pattern in Sphagnum mosses at multi-geographic scale. Front Microbiol 134
Broek AV, Lambrecht M, Vanderleyden J (1998) Bacterial chemotactic motility is important for the initiation of wheat root colonization by Azospirillum brasilense. Microbiology 144:2599–2606
Chi F, Shen S-H, Chen S-F, Jing Y-X (2004) Migration of Azospirillum brasilense Yu62 from root to stem and leaves inside rice and tobacco plants. Acta Bot Sin 46:1065–1070
Correa OS, Romero AM, Montecchia MS, Soria MA (2007) Tomato genotype and Azospirillum inoculation modulate the changes in bacteria communities associated with roots and leaves. J Appl Microbiol 102:781–786
Dobbelaere S, Croonenborghs A, Thys A, Ptacek D, Vanderleyden J, Dutto P, Labandera-Gonzalez C, Caballero-Mellado J, Aguirre JF, Kapulnik Y, Brener S, Burdman S, Kadouri D, Sarig S, Okon Y (2001) Responses of agronomically important crops to inoculation with Azospirillum. Aust J Plant Physiol 28:871–879
Drogue B, Doré H, Borland S, Wisniewski-Dyé F, Prigent-Combaret C (2012) Which specificity in cooperation between phytostimulating rhizobacteria and plants? Res Microbiol 163:500–510
Duhamel M, Vandenkoornhuyse P (2013) Sustainable agriculture: possible trajectories from mutualistic symbiosis and plant neodomestication. Trends Plant Sci 18:597–600
Faleiro AC, Pellizzaro Pereira T, Espindula E, Brod FCA, Arisi ACM (2013) Real time PCR detection targeting nifA gene of plant growth promoting bacteria Azospirillum brasilense strain FP2 in maize roots. Symbiosis 61:125–133
Fibach-Paldi S, Burdman S, Okon Y (2012) Key physiological properties contributed to rhizosphere adaptation and plant growth promotion abilities of Azospirillum brasilense. FEMS Microbiol Lett 326:99–108
Gavrilescua M, Chisti Y (2005) Biotechnology – a sustainable alternative for chemical industry. Biotech Adv 23:471–499
Gibert A, Magda D, Zard L (2015) Interplay between endophyte prevalence, effects, and transmission: insights from a natural grass population. PLoS One 10:e0139919
Giraudoux P (2016) Data analysis in ecology (Package ‘pgirmess’ Version 1.6.4) [Computer Program]. URL https://cran.r-project.org/web/packages/pgirmess/pgirmess.pdf. Accessed 13 June 2016
Guerrero-Molina M, Winik B, Pedraza R (2012) More than rhizosphere colonization of strawberry plants by Azospirillum brasilense. Appl Soil Ecol 61:205–212
Gundel PE, Martínez-Ghersa MS, Omacini M, Cuyeu R, Pagano E, Ríos R, Gersa CM (2012) Mutualism effectiveness and vertical transmission of symbiotic fungal endophytes in response to host genetic background. Evol Appl 5:838–849
Hodgson S, de Cates C, Hodgson J, Morley NJ, Sutton BC, Gang AC (2014) Vertical transmission of fungal endophytes is widespread in forbs. Ecol Evol 4:1199–1208
Holmes A, Birse L, Jackson RW, Holden NJ (2014) An optimized method for the extraction of bacterial mRNA from plant roots infected with Escherichia coli O157:H7. Front Microbiol 5:286
Huang Y, Kuang Z, Wang W, Cao L (2016) Exploring potential bacterial fungal biocontrol agents transmitted from seeds to sprouts of wheat. Biol Control 98:27–33
Hungria M, Joseph CM, Phillips DA (1991) Anthocyanidins and flavonols, major Nod gene inducers from seed of a black-seeded common bean (Phaseolus vulgaris L.) Plant Physiol 97:751–758
Iizuka M, Arima Y, Yokoyama T, Watanbe K (2002) Positive correlation between the number of root nodule primordia and seed sugar secretion in soybean (Glycine max L.) seedlings inoculated with a low density Bradyrhizobium japonicum. Soil Sci Plant Nutr 48:219–225
Jacquemyn H, Waud M, Merckx VS, Lievens B, Brys R (2015) Mycorrhizal diversity, seed germination and long-term changes in population size across nine populations of the terrestrial orchid Neottia ovata. Mol Ecol 24:329–3280
Johnston-Monje D, Raizada MN (2011) Conservation and diversity of seed associated endophytes in Zea across boundaries of evolution, ethnography and ecology. PLoS One 6:e20396
Kandasamy D, Prasad NN (1979) Colonization by Rhizobia of the seed and roots of legumes in relation to exudation of phenolics. Soil Biol Biochem 11:73–75
Kumar AV, Prasad S, Rao KN, Rao GR (1983) Gibberellin-like substances in seed and leachates of black gram (Phaseolus mungo L.) Proc Indiana Acad Sci 92:397–402
Lin S, Shen F, Young C (2011) Rapid detection and identification of free-living nitrogen fixing genus Azospirillum by 16S rRNA-gene-targeted genus-specific primers. Antonie Van Leeuwenhoek 99:837–844
Links MG, Demeke T, Gräfenhan HJE, Hemmingsen SM, Dumonceaux TL (2014) Simultaneous profiling of seed-associated bacteria and fungi reveals antagonistic interactions between microorganism within a shared epiphytic microbiome of Triticum and Brassica seeds. New Phytol 202:542–553
Lopez-Velasco G, Carder PA, Welbaum GE, Ponder MA (2013) Diversity of the spinach (Spinacia oleracea) spermosphere and phyllosphere bacterial communities. FEMS Microbiol Lett 346:146–154
Meyer F, Paarmann D, D’Souza M, Olson R, Glass EM, Kubal M, Paczian T, Rodriguez A, Stevens R, Wilke A, Wilkening J, Edwards RA (2008) The metagenomics RAST server – a public resource for the automatic phylogenetic and functional analysis of metagenomes. BMC Bioinf 89:386. https://doi.org/10.1186/1471-2105-9-386
Michiels K, Croes C, Vanderleyden J (1991) Two different modes of attachment of Azospirillum brasilense Sp7 to wheat roots. J Gen Microbiol 137:2241–2246
Ofek M, Hadar Y, Minz D (2012) Ecology of root colonizing Massilia (Oxalobacteraceae). PLoS One 7:e40117
Okon Y, Labanderra-Gonzalez C (1994) Agronomic applications of Azospirillum: an evaluation of 20 years world-wide field inoculation. Soil Biol Biochem 26:1591–1601
Oliveira LR, Rodrigues EP, Marcelino-Guimarães FC, Oliveira ALM, Hungria M (2013) Fast induction of biosynthetic polysaccharide genes IpzA, IpxE, RkpI of Rhizobium sp strain PRF 81 by common bean seed exudates is indicative of a key role in symbiosis. Funct Integr Genomics 13:275–283
Pagán I, Montes N, Milgroom MG, García F (2014) Vertical transmission selects for reduced virulence in a plant virus and for increased resistance in the host. PLOS Pathogen 10:e1004293
Palma A, Pereyra CM, Moreno Ramirez LM, Xiqui Vázquez ML, Baca BE, Pereyra MA, Lamattina L, Creus CM (2012) Denitrification-derived nitric oxide modulation biofilm formation in Azospirillum brasilense. FEMS Microbiol Lett 338:77–85
Ralser M, Querfurth R, Warnatz H-J, Lehrach H, Yaspo M-L, Krobitsch S (2006) An efficient and economic enhancer mix for PCR. Biochem Biophys Res Commun 347:747–751
Rocha RO, Morais JKS, Oliveira JTA, Oliveira HD, Sousa DO, Souza CE, Moreno FB, Monteiro-Moreira AC, de Souza Júnior JD, de Sá MF, Vasconcelos IM (2015) Proteome of soybean seed exudate contains plant defense-related proteins active against the root-knot nematode Meloidogyne inognita. J Agric Food Chem 63:5335–5343
Rodriguez-Cáceres E (1982) An improved medium for isolation of Azospirillum spp. Appl Environ Microbiol 44:990–991
Sabir A, Yazici MA, Kara Z, Sahin F (2011) Growth and mineral acquisition response of grapevine rootstocks (Vitis spp.) to inoculation with different strains of plant growth-promoting rhizobacteria. J Sci Food Agric 92:2148–2153
Salomone G, Döberriner J (1996) Maize genotype effects on the response to Azospirillum inoculation. Biol Fertil Soils 21:193–196
Scher FM, Kloepper JW, Singleton CA (1985) Chemotaxis of fluorescent Pseudomonas spp to soybean seed exudate in vitro and in soil. Can J Microbiol 31:570–574
Short GE, Lacy ML (1975) Carbohydrate exudation and pea seeds: effect of cultivar, seed age, seed color, and temperature. Phytophathology 66:182–187
Thibivilliers S, Joshi T, Campbell KR, Scheffler B, Xu D, Cooper B, Nguyen HT, Stacey G (2009) Generation of Phaseolus vulgaris ESTs and investigation of their regulation upon Uromyces appedniculatus infection. BMC Plant Biol 9:9–22
Tilman D, Blazer C, Hill J, Befort B (2011) Global food demand and the sustainable intensification of agriculture. PNAS 108:20260–20264
Trujillo-Roldan M, Valdez-Cruz N, Gonzale-Monterrubio C, Acevedo-Sanchez E, Martinez-Salinas C, García-Cabrera RI, Gamboa-Suasnavart RA, Marín-Palacio LD, Villegas J, Blancas-Cabrera A (2013) A scale-up from shake flasks to pilot-scale production of the plant growth-promoting bacterium Azospirillum brasilense for preparing a liquid inoculant formulation. Appl Microbiol Biotech 97:9665–9674
Vanstockem M, Michiels K, Vanderleyden J, Van Gool AP (1987) Transposon mutagenesis of Azospirillum brasilense and Azospirillum lipoferum: physical analysis of Tn5 and Tn5-Mob insertion mutants. Appl Environ Microbiol 53:410–415
Yaryura PM, León M, Correa OS, Kerber NL, Pucheu NL, Garíca AF (2008) Assessment of the role of chemotaxis and biofilm formation as requirements for colonization of roots and seeds of soybean plants by Bacillus amyloliquefaciens BNM339. Curr Microbiol 56:625–632
Acknowledgments
We thank John Lemon for help with plant cultivation. This study was supported with funding from the National Institutes of Health awarded to CEB (GM099703) and from the United States Department of Agriculture-National Institute of Food and Agriculture (NIFA 2017-67013-26523).
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
The authors state that there are no conflicts of interest, no research involving human participants and no research involving animals.
Electronic supplementary material
Supplemental Table S1
(PDF 56.4 kb)
Supplemental Fig. S1
(PDF 88.6 kb)
Supplemental Fig. S2
(PDF 244 kb)
Rights and permissions
About this article
Cite this article
Malinich, E.A., Bauer, C.E. The plant growth promoting bacterium Azospirillum brasilense is vertically transmitted in Phaseolus vulgaris (common bean). Symbiosis 76, 97–108 (2018). https://doi.org/10.1007/s13199-018-0539-2
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s13199-018-0539-2