Biocontrol of Gray Mold Decay in Pear by Bacillus amyloliquefaciens Strain BA3 and its Effect on Postharvest Quality Parameters

Abstract

A b s t r a c tThe economic losses caused by postharvest fruits diseases have attracted global attention. Traditional chemical fungicide could not meet the need of humans. In recent years, microbial agent which has begun to take the place of chemical fungicide comes into people's vision. The aim of this paper was to investigate the potential of Bacillus amyloliquefaciens strain BA3 for its biocontrol capability on gray mold decay of pears and its effect on postharvest quality of pears. Compared with other treatments, the inhibition effect on gray mold of washed cell suspension of B. amyloliquefaciens was the best. Consequently it was utilized in subsequent experiments. Spore germination and germ tube length of Botrytis cinerea was 18.72% and 12.85 µm treated with BA3, while the control group was 62.88% and 30.44 µm. We confirmed that increase of the concentration of B. amyloliquefaciens, improved the efficacy of BA3 in controlling gray mold decay of pears. Colonization variation of BA3 in wounds of pears was recorded. To begin with, the populations of B. amyloliquefaciens increased rapidly and remained stable. On the fourth day, there was a declining trend , after that the population increased to 4 × 10 5 CFU/wound and remained stable. BA3 had no significant effect on mass loss, titratable acidity, firmness and total soluble solids of pears that were stored at 25°C for 7 days comparing with control group. However, the effect of B. amyloliquefaciens on ascorbic acid was significantly higher than that of the control group. Our study indicates that B. amyloliquefaciens has a potential as postharvest biocontrol agent on pears.K e y w o r d s:

Antifungal mechanism of Streptomyces ma. FS‐4 on fusarium wilt of banana

“…The total volume of the reaction system was 1 ml, and the amount of mitochondrial protein was 20-40 μg. Mitochondrial respiratory chain complexes I to IV and the key enzymes, namely, succinate dehydrogenase (SDH), malate dehydrogenase (MDH) and ATP synthetase, of the tricarboxylic acid cycle were measured (Qu et al 2016).…”

“…The first three measures have disadvantages, such as environmental pollution, high costs and unstable control effects (Jeong et al 2016;Hennessy et al 2017). Biological prevention and control is environment friendly and relatively safe and effective (Qu et al 2016;Nandi et al 2017). The basis of biological control is the screening of highly effective biocontrol strains (Qu et al 2016).…”

“…Biological prevention and control is environment friendly and relatively safe and effective (Qu et al 2016;Nandi et al 2017). The basis of biological control is the screening of highly effective biocontrol strains (Qu et al 2016). Many studies have reported screening biocontrol bacteria, including Streptomyces (Xue et al 2013), Bacillus (Keikha et al 2015), Pseudomonas (Abidin et al 2016), Trichoderma (Suksaard et al 2017) and nonpathogenic F. oxysporum (Alijani et al 2019), which can prevent and control fusarium wilt.…”

“…Among them, antagonism is the main mechanism of biocontrol. The antagonists produced by biocontrol bacteria metabolism mainly include cell wall degrading enzymes, such as chitinase or glucanase (Qu et al 2016), antibacterial proteins (Hennessy et al 2017), antibacterial peptides (Potshangbam et al 2018) and volatile substances (Bagy et al 2019). Karimi et al (2017) showed that the antibacterial protein produced by Bacillus subtilis B25 metabolism can make F. oxysporum hyphae or spores swell and twist or deform, its contents can be clearly seen, and the growth and reproduction of pathogenic bacteria are inhibited.…”

The use of CT scan imaging technique to determine pear bruise level due to external loads

“…Free sugars, organic acids, free amino acids and fatty acids, minerals, and perfumes are natural components of many fruits and vegetables and they play important roles in preserving the quality of the fruit and determining its value (Chen, Wang, Wu, Wang, & Hu, 2007;Yi et al, 2016). Moreover, consuming healthy fruits reduces the risk of chronic illness as they contain numerous antioxidants (Qu, Zhao, Zhao, Liu, & Yang, 2016). Mechanical damage to fruits is mainly caused during the harvest operations; however, in packaging and sorting stages, during transportation, and in the consumer market, retailers and consumers pose mechanical damage to the fruits that can reduce their quality (Li & Thomas, 2014;Opara & Fadiji, 2018).…”