Effect of Aspergillus awamori isolates against Alternaria leaf blight of Asalio (Lepidium sativum L.) caused by Alternaria alternata

Garden cress (Lepidium sativum Linn; Family: Brassicaceae) commonly known as Asalio is a fast growing annual herb native to Egypt and West Asia [5]. It’s seeds, leaves and roots posses medicinal properties due to presence of imidazole, lepidine, semilepidinoside A and B [2] carotenes, ascorbic acid, linoleic acid, oleic acid, palmitic acid, stearic acid [7] sinapic acid and sinapin[12]. Hence its commercial demand has increased several times in different parts of India viz., states of Madhya Pradesh, Uttar Pradesh, Rajasthan, Gujarat, Maharashtra and Rajasthan more than 8000 ha are under its cultivation [8]. Asalio leaf blight caused by A. alternata is major problem for hampering medicinal property crop as well as its yield loss of the crop as it not only produces melanin but also a large variety of secondary metabolites such as carcinogenic alternariol [10], [14]. Therefore, organic solution for such menace is indispensible for retaining the therapeutic value of the crop along with higher yield. Phosphorus-solubilizing microorganisms (PSMs) are abundantly available in the rhizosphere of plants [18] where they compete with other organisms for nutrient and space and in-turn provide nutrient for growth and protection from deleterious microorganism. Many studies have shown an increase in growth and P-uptake by plants through the inoculation of PSMs (one of the component of PGPF) in pot experiments [17] and as well as in field conditions [16]. The antagonistic fungi Aspergillus are a common genus in most agricultural fields of India and are ubiquitous fungus with no specific moisture and pH requirements. Therefore, the present investigation was under taken overcome the menace of this pathogen, the Plant Growth Promoting Fungi (PGPF) with special reference to Aspergillus awamori isolates have been used to manage the disease. Abstract Asalio an important medicinal plant with significant pharmacological properties has been observed to be generally affected by many fungal pathogens in India. Phosphatesolublizing Fungi (PSF) functions in soil phosphorus cycle by increasing the bioavailability of soil phosphorus for plants and root associated fungi have been known to benefit plants and are hence referred to as plant growth promoting fungi (PGPF). Present investigation Five isolates of Aspergillus awamori namely Zinger-Z, Parthenium-P, Red gram-G, Rice leaf sheath-R, Field bean-B isolated from different rhizosphere and phylloplane were tested In-vitro and In-vivo conditions. The results showed that Aspergillus awamori isolates were IAA, Phosphorus solublizing activity, Ammonia producing activity, solublizing index, Biomass determination and efficacy tests were performed against Alternaria alternata.The IAA activity of all Aspergillus awamori isolates were minimum.However, the phosphorous solublizing and Ammonia producing activity of A. awamori-R, A. awamori-B and A. awamori-Z was higher and medium among the tested isolates.The solublizing index and Phosphate-solublizing activity of all Aspergillus awamori isolates was found significant but A. awamori-R showed highest Phosphate-solublizing activity (halo zone formation). However, the highest inhibition was recorded in A. awamori-G isolate reduction in mycelia growth when growth medium was amended with and without ZnSO4. A.awamori culture filtrates of Aspergillus awamori amended with ZnSO4 amended culture, exhibited comparatively lower mycelial growth inhibition in comparison to ZnSO4 non amended culture filtrate. The highest biomass production of A.awamori-R was recorded in both ZnSO4 amended medium and without ZnSO4 amended medium.