Trichoderma biocontrol agents can promote plant growth and stimulate the plant defense mechanisms (Papavizas, 1985; Howell, 2003; Vinale et al., 2008). The mechanisms can be described as: 18.104.22.168) Competition Bio control agents and the pathogens compete with one another for the nutrients and space to get established in the environment. This process of competition is considered to be an indirect interaction between the pathogen and the bio control agent wherein the pathogens are excluded by the way of depletion of food base and via physical occupation of site (Lorito et al., 1994). The most common cause of death of microorganisms is
The mycorrhizal associations are always being described with the term symbiotic and mutualistic. (Brundrett, 2004). The root, the internal fungal structure and the external mycelium in the soil are the main characteristics of AM fungi (Heijden & Sanders, 2002). Endomycorrhizal symbiosis was given the name arbuscular because of distinguish arrangement formed in the symbiotic root. Arbuscules are complex branched of fungal hyphae enveloped by possibly modified, invaginated plant plasma membranes that form inside the cortical cells.
They also promote the production of other hormones and in conjunction with cytokinins, they control the growth of stems, roots, and fruits, and convert stems into flowers. Auxins were the first class of growth regulators discovered. They affect cell elongation by altering cell wall plasticity. They stimulate cambium, a subtype of meristem cells, to divide and in stems cause secondary xylem to differentiate. Auxins act to inhibit the growth of buds lower down the stems (apical dominance), and also to promote lateral and adventitious root development and
Phosphorus metabolism : The endomycorrhizal symbiosis is beneficial for both fungi and plant. Fungi provide phosphorus to the plant while plant as a result give carbon to the fungi. But the phosphorus metabolism is the most important part of this association. Phosphorus is first absorbed by fungi from the soil and is stored in its cytoplasm while later fungi transport it to its vacuoles. Then these vacuolar components containing phosphoros are transported from outer mycelium of fungi to the plant.
On the beneficial side, microbes are essential for nutrient cycling and sustainability of life on earth (Sylvia, 2005). Mycorrhizal fungi are one of these functional groups. Majority of plants growing under natural conditions have fungal associations with their roots and such ‘fungus-roots’ are called mycorrhizae.The mycorrhizae may be ectotrophic or endotrophic according to the major area of fungal colonization in the roots. The fungal partner in endotrophic mycorrhizae may belong to different groups. The term mycorrhiza, fungusroot, was described in 1885 by the German forest pathologist, A.
(1994), Glick (1995) and Penrose et al. (2001), have successfully explained the biochemical properties of this enzyme and its functional roles in controlling ethylene production in higher plants. In general, the plant hormone ethylene plays important different roles in the growth of plants, such as root initiation and fruit ripening (Burg and Burg 1962; Arshad and Frankenberger 1991; Kende 1993). As a stress hormone, ethylene is involved in various stress responses induced by biotic (pathogenic attack) and abiotic (environmental) factors. Its biosynthesis starts with the S-adenosylation of methionine to S-adenosylmethionine (SAM) followed by the closing of a cyclopropane ring to form ACC.
Also, cellulose present plant cell wall is degraded by fungi like Aspergillus, Fusarium, Trichoderma and bacterial aspecies like Vibrio, Cellulomonas, Polyangia, Cytophaga, Streptomyces present in gut of earthworms. (Imshenetsky 1967,Ljungdahl and Eriksson, 1985). Bacterial species like Bacillus and Pseudomonas in addition to cellulose degradation also solubilise the soil phosphate ( Vijayakumar et al., 2009) (Imshenetsky 1967; Ljungdahl and Eriksson, 1985). On the other hand along with degradation of cellulose Aspergillus niger also degrades lignin and fungus is also known for lignin breakdown. ((Imshenetsky 1967; Ljungdahl and Eriksson, 1985; Krause et al., 2003; Malherbe and Cloete
Many play an ecologically crucial role in decomposing dead organic matter, some are an important source of antibiotics or are used in fermentation, and others, cause disease. The familiar mushrooms and toadstools are merely the fruiting bodies of organisms that exist mainly as a thread-like mycelium
It has been reported that algae produce these phytohormones in order to adapt to it environment. Cytokinins like isopentenyladenine (IPA) and zeatin has been observed in Anthronema africanum, Chlorella vulgaris and Chlamydomonas reinhardtii, it increase growth rate, oil content and stress tolerant (Tarakhovskaya et al., 2007, Lu and Xu, 2015). Abscisic acid (ABA) is produce in several cyanobacteria and algae species such as the green microalgae Dunaliella salina and Chlorella, it function as a stress molecule especially for salt, osmotic pressure and drought (Lu and Xu, 2015, Jiraskova et al., 2009). Moreover, auxins like indole acetic acid (IAA) have been identified in macroalgae Nerocystis and in cyanobacteria Nostoc and Anabaena, and it play essential role in cell-cell positioning (Rastogi and Sinha, 2009, Crouch and van Staden, 1993). Gibberellins like substances is well documented in many algae species as in brown algae Ecklonia radiate and green algae species Enteromorpha prolifera (Ulva prolifera), Chlamydomonas and Chlorella, its action includes regulation of cell growth and senescence (Crouch and van Staden, 1993, Lu and Xu,
yeast produce active cell division fast growing plants for ex roots. benefits are helping properties in soil, also big help in human health. importance in yeast is improvement of bioavailability of minerals in hydrolysis phytate. yeast plays a big part of fermentation from many ingredients in foods. yeats can be know as a immune system booster .