Rhizospheric actinomycetes from organic crops of native potato (Solanum tuberosum): isolation, phenotypic characterization, molecular identification, and impact on biocontrol of Phytophthora infestans (Mont.) de Bary
SCIENTIA AGROPECUARIA
Authors: Chumpitaz Bermejo, Astrid; Caro Castro, Junior; Cruz Hilacondo, Wilbert; Leon Quispe, Jorge
Abstract
Potato (Solanum tuberosum L.) is the fourth most consumed food crop in the world, whose production in Peru is diminished due to phytosanitary problems and high costs of chemical fertilizers. In the present work, 32 actinomycetes isolated from the rhizosphere of organic native potato crops collected in the town of Cabana, Lucanas, Ayacucho, were characterized phenotypically and evaluated for their in vitro antagonistic capacity against Oomycete phytopathogen Phytophthora infestans. The characterization tests showed that 97% of the actinomycetes were able to assimilate glucose, sucrose, and mannitol; as well as producing extracellular enzymes like amylases (100%) and cellulases (50%). Furthermore, the growth in laboratory culture was better in the range of pH 5.5-8.5 and temperature 28-30 degrees C. From the tests of antagonism in oat agar (71.9%) and rye agar (31.2%), three strains were selected according to the native potato variety were selected as CAB10-J2 (Ccompis), CAB9-CA4 (Cuchipa-akan) and CAB5-F5 (Futis) with pathogen inhibition rates of 80.05, 77.47 and 37.5% respectively. The strains were identified by molecular tests as members of the genus Streptomyces and owners of polyketide synthase (PKS) genes. It is concluded that the rhizospheric actinomycetes of potato are producers of bioactive compounds capable of remarkably inhibiting the pathogen Phytophthora infestans, being able to be considered candidates in biological control programs of the "potato blight".
Stability of the Metabolite Signature Resulting from the MIPS1 Mutation in Low Phytic Acid Soybean (Glycine max L. Merr.) Mutants upon Cross-Breeding
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
Authors: Gossner, Sophia; Yuan, Fengjie; Zhou, Chenguang; Tan, Yuanyuan; Shu, Qingyao; Engel, Karl-Heinz
Abstract
The low phytic acid (lpa) soybean (Glycine max L. Merr.) mutant Gm-lpa-TW-1-M, resulting from a 2 bp deletion in GmMIPSI, was crossed with a commercial cultivar. F3 and F5 progenies were subjected to nontargeted GC-based metabolite profiling, allowing analysis of a broad array of low molecular weight constituents. In the homozygous 1pa mutant progenies the intended phytic acid reduction was accompanied by remarkable metabolic changes of nutritionally relevant constituents such as reduced contents of raffinose oligosaccharides and galactosyl cyclitols as well as increased concentrations in sucrose and various free amino acids. The mutation-induced metabolite signature was nearly unaffected by the cross-breeding and consistently expressed over generations and in different growing seasons. Therefore, not only the primary MIPSI 1pa mutant but also its progenies might be valuable genetic resources for commercial breeding programs to produce soybean seeds stably exhibiting improved phytate-related and nutritional properties.