Streptomyces sp. G21 mitigates postharvest mango anthracnose by tuning ROS and phenylpropanoid metabolism

Area of Science:

• Plant Pathology
• Microbiology
• Biotechnology

Background:

• Mangoes are economically important but prone to postharvest diseases like anthracnose, causing significant quality loss.
• Colletotrichum gloeosporioides is a major pathogen responsible for mango anthracnose.
• Biological control offers a sustainable alternative to chemical treatments for postharvest disease management.

Purpose of the Study:

• To evaluate the biocontrol efficacy of Streptomyces sp. G21 against mango anthracnose.
• To investigate the effects of G21 on mango fruit quality during storage.
• To elucidate the underlying mechanisms of G21-induced disease resistance.

Main Methods:

• Application of Streptomyces sp. G21 to mango fruits.
• Assessment of disease index and key quality parameters (firmness, acidity, ascorbic acid, phenols).
• Measurement of defense enzyme activities (SOD, CAT, POD) and gene expression (POD, PAL, 4CL).
• Analysis of reactive oxygen species (ROS) levels and lipid peroxidation.
• Identification of phenylpropanoid compounds and regulatory genes (MiPAL6, Mi4CL-like9).

Main Results:

• G21 treatment significantly reduced the disease index of mango anthracnose.
• G21 application maintained fruit firmness, titratable acidity, ascorbic acid, and total phenol content.
• Enhanced activities of SOD, CAT, and POD enzymes and their gene expression were observed.
• Reduced ROS accumulation and membrane lipid peroxidation indicated less oxidative damage.
• G21 modulated phenylpropanoid synthesis, with MiPAL6 and Mi4CL-like9 identified as potential mediators.

Conclusions:

• Streptomyces sp. G21 effectively controls mango anthracnose and preserves fruit quality.
• G21 enhances the plant's natural defense system, offering a sustainable biocontrol strategy.
• This study highlights the potential of G21 for reducing postharvest losses in mangoes.