Improved Yield of Micropropagated Sugarcane Following Inoculation by Endophytic Burkholderia vietnamiensis

Abstract

During a survey of nitrogen-fixing Burkholderia associated with sugarcane in Tamil Nadu, some endophytes were isolated on PCAT medium. Isolation was based on the use of the selective PCAT medium. Four isolates were studied, all belonging to the genus Burkholderia. One of them, MG43 was consistently more active in reducing acetylene and was identified as Burkholderia vietnamiensis. This isolate was used to inoculate micro-propagated sugarcane plantlets in a comparison with two other diazoptrophs, viz. Gluconacetobacter diazotrophicus T and Herbaspirillum seropedicae T . Inoculated plants and uninoculated controls were used in a pot experiment followed by two field experiments under different rates of nitrogen fertilisers. MG43 and G. diazotrophicus performed best in sugarcane, their natural host. Biomass increase due to MG43 inoculation reached 20% in the field. Inoculated plants were heavily colonised by the inoculated bacterium (up to 115,000 CFU g )1 root fresh weight). Inoculation by a combinaison of the three strains performed less well than inoculation by a single MG43 suspension. Ecological implications are discussed, as well as the potential of these bacteria to provide a feasible alternative to higher N fertilisers rates in a low input and long term sustainable rural economy.

Inoculation of sugarcane with diazotrophic bacteria

“…The results obtained in this study corroborate several studies in the literature. Govindarajan et al (2006) evaluated the inoculation of Burkholderia vietnamiensis, strain MG43, in the varieties Co 86032 and Co 86027 of micropropagated sugarcane after different evaluation periods up to 12 months after planting, and found that inoculation with strain MG43 promoted increases of 20 and 19 % in dry matter production of Co 86032 and Co 86027, respectively. Testing the same inoculum as in this study in a medium texture Hapludult, Silva et al (2009) found that stalk yield increased by 50 Mg ha -1 in variety RB72454 and 30 Mg ha -1 in variety RB867515, 11 months after planting, compared to the absolute control; these increases were similar to those recorded in the control fertilized with 120 kg ha -1 N. Similar results to those mentioned above were reported by Schultz et al (2012) in studies carried out for two years in a Fluventic Eutrudept in the region of Campos dos Goytacazes, Rio de Janeiro, for variety RB867515.…”

Multichromosomal Genome Structure and Confirmation of Diazotrophy in Novel Plant-Associated Burkholderia Species

“…15 N 2 isotope dilution assays revealed unambiguous diazotrophy in these novel species. nifH gene sequence analysis, often used to determine phylogenetic relatedness among diazotrophs, showed tight clusters of Burkholderia species, which were clearly distinct from those of other diazotrophs.…”

The Tomato Rhizosphere, an Environment Rich in Nitrogen-Fixing Burkholderia Species with Capabilities of Interest for Agriculture and Bioremediation

“…Although the complete genome of B. xenovorans LB400 T was recently sequenced (12), it is noteworthy that the four extant B. xenovorans strains described in diverse studies have been randomly recovered from different environments and widely distant geographical regions, and there are no studies on the distribution of this PCB-degrading, nitrogen-fixing species or its association with plants. Emphasis has been given to studies of the isolation, taxonomy, and distribution of Burkholderia species related to human opportunistic pathogens, especially the B. cepacia complex species found in cystic fibrosis patients (33,45,52; for reviews, see references 15 and 42). In contrast, few studies have been performed on the overall diversity of the genus Burkholderia (61,63), even though nonpathogenic Burkholderia species are frequently recovered from different environments (6,40,70), and despite their biotechnological potential in bioremediation and other applications (34,70; for a review, see reference 48).…”