Formulations of the endophytic bacteriumBacillus subtilisTu-100 suppressSclerotinia sclerotiorumon oilseed rape and improve plant vigor in field trials conducted at separate locations

Abstract

Sclerotinia sclerotiorum causes serious yield losses in crops in the People's Republic of China. Two formulations of oilseed rape seed containing the bacterium Bacillus subtilis Tu-100 were evaluated for suppression of this pathogen in field trials conducted at two independent locations. The pellet formulation significantly reduced disease (incidence and disease index) and increased plant dry mass, while the wrap formulation significantly reduced disease incidence and significantly increased plant dry mass at both field locations. Mean seed yield per 120 plants with both formulations of isolate Tu-100 was significantly greater than the appropriate controls, but at only one of the locations. Both formulations provided stable B. subtilis Tu-100 biomass (≥10(5) CFU·g(-1)) and seed germination (≥85%) over a 6 month period at room temperature. Polymerase chain reaction and DNA sequence analysis identified ituC and ituD, and bacAB and bacD in the genome of isolate Tu-100. These genes are involved in the biosynthesis of iturin and bacilysin. Iturin was detected in culture filtrates from isolate Tu-100, with thin layer chromatography. Detection of bacilysin was not attempted. Experiments reported here indicate the commercial viability of B. subtilis Tu-100 for suppression of S. sclerotiorum on oilseed rape.

Plant Nutrient Dynamics in Stressful Environments

“…Seed priming with water and micronutrients was beneficial, in particular where stress affected juvenile plants [69]. As could be expected, seed priming with micronutrients enhanced their concentration in the seeds, while the content in the progeny seeds remained unaffected [73]. Calcium sulphate and calcium chloride proved to be more effective at enhancing germination of wheat under salt stress than sodium chloride [74].…”

“…PHR1 regulates many Pi-related genes ( [50]), such as the miRNA399 that eventually targets Phosphate 2 (PHO2) transcripts. The reduction of PHO2 protein abundance leads to the accumulation of PHT1 and PHO1 proteins ( [72]) and consequently an increase of the plant capacity to uptake Pi and translocate Pi to shoots ( [73]). Noteworthy, the proper functioning of this signalling pathway requires the contribution of many others genes such the SUMO E3 ligase SIZ1 ( [32]), PHOSPHATE TRANSPORTER TRAFFIC FACILITATOR1 (PHF1), ( [51]) and NITROGEN LIMITATION ADAPTATION (NLA), ([60]).…”

“…Drought-induced senescence is associated with numerous morphological, physiological and molecular modifications in several species including nutrient remobilization from senescing organs (mainly leaves, and to a much smaller extent nodules in legumes) to young tissues (leaves or seeds), thus compensating for the nutrient uptake deficit that results from low soil water content [72,73]. While much work has been conducted to evaluate the consequences of drought on seed nutrient contents, to our knowledge studies focusing on the effect of drought specifically on nutrient remobilization from leaves (estimated from a net balance during senescence) are very scarce.…”

Sustainable Agriculture—Enhancing Environmental Benefits, Food Nutritional Quality and Building Crop Resilience to Abiotic and Biotic Stresses

“…Two seed treatment formulations of Bacillus subtilis BY-2 and of B. subtilis Tu-100, and spray applications of these two isolates at flowering, resulted in significantly lower disease incidence than the non-treated control and a significantly greater yield than this control in field trials conducted at a few locations. B. megaterium A6 was also shown to control S. sclerotiorum on oilseed rape at a few field locations when applied as a seed treatment formulation [73][74][75]. Control by these strains at these field locations compared favorably to that provided by the carbendazim chemical spray control applied at flowering.…”

Biological control of the soil-borne fungal pathogen Sclerotinia sclerotiorum –– a review

“…In most cases Pseudomonas showed multiple mechanisms in the biocontrol of diseases caused by S. sclerotiorum. Zazzerini 1987;Zhang and Fernando 2004a;Chitrampalam et al 2008;Hu et al 2011;Zeng et al 2012a, b;Monteiro et al 2013;Hu et al 2014;Kamal et al 2015 Bacillus megaterium Hu et al 2013;Hu et al 2014 Bacillus amyloliquefaciens Fernando et al 2007 Bacillus cereus Zazzerini 1987;Kamal et al 2015 Erwinia herbicola (Pantoea agglomerans) Godoy et al 1990b;Yuen et al 1994 Pseudomonas chlororaphis Zhang and Fernando 2004b;Savchuk and Fernando 2004;Fernando et al 2007;Selin et al 2010 Pseudomonas fluorescens Bin et al 1991;Expert and Digat 1995 Pseudomonas putida Expert and Digat 1995…”