PENICILLIUM SPP. AS PHYTOAUGMENTOR
Rhizospheric fungi have the ability to stimulate plant growth are designated as ‘PGPF (Hyakumachi, 1994). PGPF is nonpathogenic soil- inhabiting saprophytes, which have been reported for growth promotion in several crop plants and providing protection against diseases (Shivanna et al., 1996). Such PGPF belongs to various genera, including Fusarium, Penicillium, Phoma, and Trichoderma. Few species of PGPF have been stated to prompt the SR in contrast to numerous phytopathogens (Shoresh et al., 2005). Hypocrea rufa is a common inhabitant of the rhizosphere and decisively recognized as a bio-control agent of soil-bome plant pathogens (Hannan et al., 2004). A praiseworthy amount of research has been focused on the mycoparasitic nature of H. rufa and its contribution in plant overall growth has been promoted. H rufa controls the plant-pathogenic fungi by three different mechanisms, antibiosis, competition, and mycoparasitism (John et al., 2010). The multifaceted development of mycoparasitism necessitates the production of plenty of cell-wall digesting enzymes, for instance, chitinases, polysaccharide lyases, cellulases, and proteases in addition lipases which degrade the cell wall of fungi.
4.8.1 PENICILLIUM BILAIAE
Penicillium bilaiae is a species of inborn soil fungus that can be cast-off as a PGPF. R. Kucey was the first to identify that the organic acids are excreted by the microorganism, and then it assisted to solubilize soil-bound phosphate. The organism can provide feedstuff on plant waste foodstuffs and even can augment phosphate uptake by the root structure and establish symbiosis with several plant species. Inborn soil populations are often squat and can be amplified by using them as an agricultural inoculant. Penicillium bilaiae is a fungal microorganism applied to several crop species to enhance soil-bound phosphorous uptake (Kucey, 1983). It is also used to promote soil-bound phosphorous uptake in several crop species such as wheat, canola, and pulse crops. Phosphate-solubilizing soil and rhizosphere microorganisms have been distinguished by their relative abilities to dissolve calcium phosphate and apatite in pure culture and in connotation through plant roots (Gaur et al., 1973). P bilaiae can also produce citric acid and it also helps to break down of CaP04. The use of efficient phosphate-solubilizing microorganisms (PSM) opens up a new horizon for better crop productivity besides sustaining soil health.
4.8.2 PENICIL LIUM MENONORUM
Penicillium menonorum is a mono-verticillate, non-vesiculate species of the genus of Penicillium which was isolated from rhizosphere soil in Korea. The fungal isolate was found to exhibit plant growth-promoting activity through indole acetic acid (IAA) and siderophore production, as well as P solubilization. It produced 9.7 mg/L IAA and solubilized 408 mg of Ca3P04/L. It also increased the diy biomass of cucumber roots by 57% and shoots by 52% in an experiment earned out. In the further experiment, it was also observed that the chlorophyll content was increased by 16%, starch by 45%, protein by 22%, and phosphate contents by 14%. This fungus also produces various useful enzymes like dehydrogenase and acid phosphatase. And it has increased its activities by 30% and 19% respectively. These results validate that the isolate has potential PGP attributes, and therefore, it can be well-thought-out as a new fungus to enhance soil fertility and promote plant growth.
4.8.3 PENICILLIUM SIMPLICISSIMUM
Penicillium simplicissimum is an anamorph species that belong to the genus of Penicillium that can be used for plant growth promotion. This species is present on food; besides, its primary habitation is in putrefying vegetation. Penicillium simplicissimum was evaluated for its ability to induce resistance against Cucumber mosaic virus (CMV) in Arabidopsis thaliana and tobacco plants. P. simplicissimum has the characteristic to degrade polyethylene as a sole carbon source.
4.8.4 PENICILLIUM CITRINUM
Penicillium citrinum is an anamorph, mesophilic fungus species that fit into genus of Penicillium, which produces tanzawaic acid and helps in inhibiting bacterial conjugation (Lopatkin et al., 2016). Penicillium citrinum is often found on moldy citrus fruits and occasionally it occurs in tropical spices and cereals. Penicillium citrinum is well-known for production of mycotoxin citrinin and cellulose digesting enzymes such as cellulose, endoglucanase, as well as xylulase. Gibberellins producing ability of this fungus is also been found. Numerous studies disclose that Penicillum spp. reinforced plant growth and development by its phosphate solubilization. Pandey et al. (2008) in their research displayed that eight species of Penicillum with the ability in making clear zone by in vitro airing. Many researches also testified the ability and effectiveness of Penicillium as bio-fertilizer and can be castoff in field (Hakim et al., 2017).