Yasmeen Siddiqui

Effect of a novel edible composite coating based on gum arabic and chitosan on biochemical and physiological responses of banana fruits during cold storage.

The composite effects of gum arabic (GA) (5, 10, 15, and 20%) and chitosan (CH) (1.0%) on the biochemical and physiological characteristics of banana fruits stored at 13 ± 1 °C and 80 ± 3% relative humidity (RH) for 28 days and afterward for 5 days at simulated marketing conditions (25 °C, 60% RH) were investigated. Significant (P ≤ 0.05) differences were observed for the entire GA plus CH treatments as compared to the control. However, the results showed that after 33 days of storage, the weight loss and soluble solids concentration of fruits treated with 10% GA plus 1.0% CH composite coating were 24 and 54% lower, whereas fruit firmness, total carbohydrates, and reducing sugars were 31, 59, and 40% higher than the control, respectively. Furthermore, the composite edible coating of 10% GA plus 1.0% CH delayed color development and reduced the rate of respiration and ethylene evolution during storage as compared to the control. Similarly, sensory evaluation results also proved the effectiveness of 10% GA plus 1.0% CH composite coating by maintaining the overall quality of banana fruits. Consequently, the results of scanning electron microscopy also confirmed that the fruits coated with 10% GA plus 1.0% CH composite edible coating had very fewer cracks and showed a smooth surface. These findings suggest that 10% GA plus 1.0% CH as an edible composite coating can be used commercially for extending the storage life of banana fruits for up to 33 days.

Potential of chitosan-loaded nanoemulsions to control different Colletotrichum spp. and maintain quality of tropical fruits during cold storage

To investigate the antifungal activity of conventional chitosan and chitosan‐loaded nanoemulsions against anthracnose caused by Colletotrichum spp. isolated from different tropical fruits.

Effect of seed bacterization on plant growth response and induction of disease resistance in chilli.

This study aimed to examine the induction of disease resistance, and growth response in chilli plants elicited by plant growth promoting endophytic bacteria [Pseudomonas aeruginosa (UPMP3), Burkholderia cepacia (UPMB3), and Serratia marcescens (UPMS3)]. Seed bacterization with UPMP3 and UPMB3 significantly increased peroxidase (PO), polyphenol oxidase (PPO), and phenylalanine ammonia-lyase (PAL) activities. This increase corresponded to greater reduction in pre- and post-emergence damping-off caused by Sclerotium rolfsii. UPMS3 alone or as mixture with UPMP3 and UPMB3 did not show any significant reduction in disease incidence. However, all the isolates tested did not inhibit the seed germination and seedling establishment in chilli.

Biocontrol of Plant Parasitic Nematodes by Fungi: Efficacy and Control Strategies

Increasing knowledge and growing concern about the elevated cost of inorganic fertilizers or chemical pesticides with their vast applications on various crop plants has raised interest in the alternative method of plant disease protection caused by plant parasitic nematodes. These alternative methods are not only cost-effective but also eco-friendly to the environment and human health. Among the various rhizospheric microorganisms, opportunistic fungi like Paecilomyces lilacinus, Pochonia chlamydosporia, and arbuscular mycorrhizal (AM) fungi have the potential to reduce the severity of diseases caused by plant parasitic nematodes and also improved the plant growth and biomass production. This chapter provides an overview on the biocontrol potential of opportunistic as well as AM fungi on the growth and development of various crop plants. The details about the interactions between these fungi and plant parasitic nematodes have been discussed. An overview of the recent cost-effective technologies used for the mass propagation of these beneficial rhizospheric microorganisms is also discussed.

Inhibition and kinetic studies of cellulose- and hemicellulose-degrading enzymes of Ganoderma boninense by naturally occurring phenolic compounds

Ganoderma sp, the causal pathogen of the basal stem rot (BSR) disease of oil palm, secretes extracellular hydrolytic enzymes. These play an important role in the pathogenesis of BSR by nourishing the pathogen through the digestion of cellulose and hemicellulose of the host tissue. Active suppression of hydrolytic enzymes secreted by Ganoderma boninense by various naturally occurring phenolic compounds and estimation of their efficacy on pathogen suppression is focused in this study.

Bio-Efficacy of Microbial Infused Rice Straw Compost on Plant Growth Promotion and Induction of Disease Resistance in Chili

ABSTRACT Microbial fortified organic amendment in chili cultivation may affect plant development and disease suppression. Microbial infused rice straw compost, commercial rice straw compost, and fungicide Benomyl for chili (Capsicum annum L.) cultivation and control of Sclerotium foot rot were studied under glass house condition. Chili seed cv. Kulai were sown in the Sclerotium rolfsii infested and non-infested soil. After two weeks, five healthy seedlings were transplanted into planting bags. Growth performance and development of disease symptoms associated with S. rolfsii foot rot infection were assessed. Applying microbial infused rice straw compost increased seed germination and plant growth, and suppressed development of foot rot compared to using commercial rice straw compost and the Benomyl. A higher disease reduction (84.6%) occurred with 15 Mg · ha−1 microbial infused rice straw compost (62.7%), followed by Benomyl (53.8%), and 15 Mg · ha−1 commercial rice straw compost (46.2%). Application of microbial infused rice straw compost at 15 Mg · ha−1 yielded optimum seed germination and seedling establishment, plant growth, and disease suppression. Microbial infused rice straw compost is a good alternative to chemical fungicide in controlling Sclerotial disease in chili.

Colletotrichum gloeosporioides (Anthracnose)

Abstract Anthracnose, caused by the fungus Colletotrichum gloeosporioides, is the most widespread and serious postharvest disease of many tropical fruits including mango, papaya, pitaya, and avocado. The most damaging phase of the disease begins as a quiescent infection, when the fruit is in the preclimacteric phase of development. Growth of the pathogen is resumed only after harvest when the fruit starts to ripen and postharvest anthracnose develops leading to significant decay losses during storage and marketing. The disease is traditionally controlled by synthetic chemical fungicides and hot water treatment, in the case of papaya and mango. However, when harvested fruits are treated with fungicides, there is greater likelihood of direct human exposure to them and of development of resistance in pathogens. This chapter brings to light the key emerging environmentally friendly techniques, in particular, use of edible coatings and essential oils. It is well recognized that there is a need to develop new and effective methods of controlling postharvest diseases that are perceived as safe by the public and pose negligible risk to human health and the environment.

Inhibition and kinetic studies of lignin degrading enzymes of Ganoderma boninense by naturally occurring phenolic compounds

Lignolytic (lignin degrading) enzyme, from oil palm pathogen Ganoderma boninense Pat. (Syn G. orbiforme (Ryvarden)), is involved in the detoxification and the degradation of lignin in the oil palm and is the rate‐limiting step in the infection process of this fungus. Active inhibition of lignin‐degrading enzymes secreted by G. boninense by various naturally occurring phenolic compounds and estimation of efficiency on pathogen suppression was aimed at.

DETERMINATION OF BIOLOGICAL EFFICIENCY AND ANTIOXIDANT POTENTIAL OF GANODERMA LUCIDUM CULTIVATED UTILISING DIFFERENT AGRO-WASTES

This study investigates the cultivation of Ganoderma lucidum using different agricultural biomasses from Malaysia. Five different combinations of rubber wood sawdust, empty fruit bunch fiber, and mesocarp fiber from oil palm, alone and in combination, were used to cultivate G. lucidum. Although all the substrate combinations worked well to grow the mushroom, the highest biological efficiency was obtained from the combination of empty fruit bunch fiber with sawdust. A total yield of 27% was obtained from empty fruit bunch fiber with sawdust, followed by sawdust (26%), empty fruit bunch fiber (19%), mesocarp fiber with sawdust (19%), and mesocarp fiber (16%). The quality of mushrooms was proved by proximate analysis and detection of phenolic compounds and flavonoids. The antioxidant activity verified by DPPH, ferric-reducing ability of plasma, and ABTS analyses revealed that the empty fruit bunch fiber with sawdust had higher activity than the other substrates.

Bio-intensive Management of Fungal Diseases of Fruits and Vegetables Utilizing Compost and Compost Teas

Compost has been used in agriculture and horticulture for a long time as a fertilizer or a soil conditioner. However, in recent years the focus has been placed on the disease-suppressive effects of the compost and its aqueous extracts. Several composts and their water extracts have been investigated on different diseases especially on those caused by soilborne pathogens throughout the world. Conversely, an increase in disease incidence has also been reported. Therefore, it remains the fact that compost application can suppress the diseases in positive, neutral, and even negative manner. This makes the utilization of compost intricate as a robust prevalent approach to mitigate plant diseases. The mechanisms involved in the disease suppression are not fully known. The disease-suppressive effect of the compost could be attributed to various mechanisms including the presence of antagonistic microbes and unidentified chemical factors in them, antibiosis, and induction of systemic resistance in plants and improvement of the overall health of plants. This chapter focuses on the influence of compost and compost teas on the suppression of foliar and soilborne fungal diseases of fruits and vegetables. The factors limiting and enhancing their efficacy will also be discussed.