Abstract
Fusarium wilt of banana cannot be effectively controlled by current control strategies. The most virulent form that caused major losses in the banana production is Fusarium oxysporum f. sp. cubense Tropical Race 4 (Foc-TR4). Biocontrol of Foc-TR4 using microbial antagonists offers a sustainable and eco-friendly alternative. A consortium of biocontrol agents (BCAs), Pseudomonas aeruginosa DRB1 and Trichoderma harzianum CBF2 was formulated into pesta granules, talc powder, alginate beads and liquid bioformulations. Previous study indicated bioformulations containing both BCAs successfully reduced the disease severity of Foc-TR4. To date, the biocontrol mechanism and plant growth promoting (PGP) traits of a consortium of BCAs on infected bananas have not been explored. Therefore, the study was undertaken to investigate the effect of a consortium of DRB1 and CBF2 in the growth and biochemical changes of Foc-TR4 infected bananas. Results indicated pesta granules formulation produced bananas with higher biomass (fresh weight: 388.67 g), taller plants (80.95 cm) and larger leaves (length: 39.40 cm, width: 17.70 cm) than other bioformulations. Applying bioformulations generally produced plants with higher chlorophyll (392.59 μg/g FW–699.88 μg/g FW) and carotenoid contents (81.30 μg/g FW–120.01 μg/g FW) compared to pathogen treatment (chlorophyll: 325.96 μg/g FW, carotenoid: 71.98 μg/g FW) which indicated improved vegetative growth. Bioformulation-treated plants showed higher phenolic (49.58–93.85 μg/g FW) and proline contents (54.63 μg/g FW–89.61 μg/g FW) than Foc-TR4 treatment (phenolic: 46.45 μg/g FW, proline: 28.65 μg/g FW). The malondialdehylde (MDA) content was lower in bioformulation treatments (0.49 Nm/g FW–1.19 Nm/g FW) than Foc-TR4 treatment (3.66 Nm/g FW). The biochemical changes revealed that applying bioformulations has induced host defense response by increasing phenolic and proline contents which reduced root damage caused by Foc-TR4 resulting in lower MDA content. In conclusion, applying bioformulations containing microbial consortium is a promising method to improve growth and induce significant biochemical changes in bananas leading to the suppression of Foc-TR4.
Highlights
Fusarium wilt of banana, caused by the fungal pathogen
P. aeruginosa DRB1 produced 4.1 μg/mL of Indole acetic acid (IAA) which was in agreement with Khare and Arora (2010) whereby P. aeruginosa strain TO3 produced similar amount of IAA (4.8 μg/mL)
The application of pesta granules containing a consortium of P. aeruginosa DRB1 and T. harzianum CBF2 has improved the overall growth in Foc-Tropical Race 4 (TR4) infected bananas compared to other bioformulations
Summary
Fusarium wilt of banana, caused by the fungal pathogen. Foc-TR4 is found distributed in 19 of the 135 countries that produce bananas and its rapid spread has received tremendous global interest in seeking effective management methods (Zheng et al 2018). Foc is a difficult soil-borne fungus to control due to several reasons: (1) its persistent survival in soil for more than 20 years even in the absence of the banana host or within alternative host which do not show disease symptoms; (2) as a vascular pathogen that escapes nonsystemic fungicides and non-endophytic biocontrol agents (BCAs); (3) spread through soil, planting materials, workers and farm machinery; and (4) the monoculture of popular banana varieties such as Cavendish (Bubici et al 2019). Biological control is a sustainable alternative that utilises microbial antagonists or BCAs for the suppression of plant disease (Raza et al 2016). Compared to other available methods, developing a biocontrol regime for Foc is not costly, it is sustainable and environmental-friendly method of managing Foc (Wang et al 2017)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
