Spore Types and Spore Production of Ramularia areola for Screening Cotton Germplasm for Resistance

Spore production ofRamularia areolahas always been a difficult task. Brazilian isolates ofR. areolaproduce spores of variable size and shape. The typical spores are 3 septate, rarely 4 and 5 septate, together with abundant single celled oblong to round bodies—a phenomenon not reported earlier forR. areola. Budding of spores is a continuous process as observed in our isolates. By repeated culturing the pathogen either ceases to produce typical spores or loses its pathogenic character. To solve this problem, a technique was developed to produce large quantity of typical spores under laboratory conditions. Sporulating cultures produced on Petri plates containing V8 juice-agar were kept on the laboratory bench till they became dry and then stored at 5°C for reisolation and/or for production of fresh inoculum. In such dried cultures spores remain viable for a period of over 12 months, and hence isolates ofR. areolaoriginatedfrom different geographic regions can be maintained in sporulating form. Results of the present investigation would aid cotton breeders and pathologists in screening germplasm resistant toRamulariaand in other genetical studies under glasshouse conditions.

Optimization of Mycelial Culture Conditions and Fructification of Lentinus Species Using Rice Straw and Sawdust Based Substrates

Lentinus(Basidiomycota,Polyporaceae)species are naturally-occurring mushrooms with nutritional and pharmacological importance.Unlike shiitake Lentinula edodes,a widely cultivated mushroom,Lentinus species are often ignored because they are underutilized and unpopular.However,like shiitake,Lentinus spp.could also be valuable resources of functional food and bioactive compounds.It is therefore of high interest to understand their cultural requirements leading to their efficient biomass production.Thus,this study established the optimal culture conditions for the maximum mycelial growth of seven wild strains under four Lentinus species.Their cultivation potentials were also determined using rice straw and sawdust(7:3 v/v)substrate formulation.Mycelia of all Lentinus strains evaluated favorably grew on coconut water gulaman(local crude agar)and other culture media for specific strain with suitable pH ranging from 5.0 to 8.0.Aeration was not a major physical factor for all Lentinus strains except L.squarrosulus strain 1,which favored sealed condition.Both lighted and dark conditions were found suitable for both strains of L.sajor-caju,L.strigosus strain 2 and L.swartzii whereas both strains of L.squarrosulus and L.strigosus strain 1 favorably grew in lighted condition.However,all Lentinus strains evaluated recorded the highest mycelial growth rates and thick mycelia at 30℃.In terms of fruiting body production,all Lentinus strains demonstrated cultivation potential.The seven Lentinus strains completely colonized the substrate for 18.0-25.6 days and initiated primordia for 21.6-33.5 days.The highest yield(52.5 g bag^(-1))and biological efficiency(10.5%)was recorded in L.strigosus strain 1,whereas the lowest was noted in L.strigosus strain 2 with 21.1 g bag^(-1) yield and 4.2%biological efficiency.L.sajor-caju strain 2 and L.squarrosulus strain 1 showed the widest cap diameter and longest stipe,respectively.The mycelial growth and fruiting body performance of Lentinus may vary depending on species and strains.Altogether,the seven new wild strains of Lentinus can be artificially cultivated by providing the nutritional and physical requirements.

Reactive oxygen species and antioxidant properties from mushrooms

Preventive medicine and food industry have shown an increased interest in the development of natural antioxidants,since those most commonly used synthetic antioxidants may have restricted use in food.This could explain why there is currently much research on the antioxidant properties from natural products such as mushrooms.Many mushrooms have been reported to possess antioxidant properties,which enable them to neutralize free radicals.The oxygen molecule is a free radical,which lead to the generation of the reactive oxygen species and can damage the cells.Cell damage caused by free radicals appears to be a major contributor to aging and degenerative diseases.Mushrooms antioxidant components are found in fruit bodies,mycelium and culture both,which include polysaccharides,tocopherols,phenolics,carotenoids,ergosterol and ascorbic acid among others.Fruit bodies or mycelium can be manipulated to produce active compounds in a relatively short period of time,which represent a significant advantage in antioxidant compounds extraction from mushrooms.Antioxidant compounds may be extracted to be used as functional additives or mushrooms can be incorporated into our food regime,representing an alternative source of food to prevent damage caused by oxidation in the human body.