Correct option is C
Puccinia graminis is an obligate biotroph, meaning it relies entirely on living host tissue to complete its lifecycle. It is a pathogenic fungus responsible for wheat stem rust, and it cannot survive without its host, making it an obligate biotroph.
Botrytis cinerea is a necrotrophic fungus, meaning it kills host tissue to feed on it.
Phytophthora infestans is a hemibiotroph, initially living in a biotrophic manner but later transitioning to a necrotrophic phase.
Trichoderma harzianum is a beneficial fungus that acts as a biocontrol agent and is not classified as an obligate biotroph.
Information Booster:
Obligate biotrophs require living host tissue to complete their life cycles. These pathogens are highly dependent on their hosts for nutrition and survival.
Necrotrophs, like Botrytis cinerea, kill their host cells to obtain nutrients.
Hemibiotrophs, such as Phytophthora infestans, begin their lifecycle as biotrophs but eventually shift to a necrotrophic lifestyle.
Puccinia graminis, as an obligate biotroph, causes wheat stem rust by infecting living plant tissues and deriving nutrients from them.
