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121.
Isolation of a phytotoxic isocoumarin from Diaporthe eres‐infected Hedera helix (English ivy) and synthesis of its phytotoxic analogs 下载免费PDF全文
Kumudini M Meepagala William E Briscoe Natascha Techen Robert D Johnson Brandon M Clausen Stephen O Duke 《Pest management science》2018,74(1):37-45
BACKGROUND
The fungus Diaporthe eres was isolated from a fungal pathogen‐infected leaf of Hedera helix (English ivy) exhibiting necrosis. It is hypothesized that the causative fungus produces phytotoxins as evidenced by necrotic lesions on the leaves.RESULTS
The fungus was isolated and grown in Czapek Dox broth culture medium and potato dextrose broth culture medium and identified as Diaporthe eres. The ethyl acetate extracts of the culture broths were phytotoxic to lettuce (Lactuca sativa) and bentgrass (Agrostis stolonifera). 3,4‐Dihydro‐8‐hydroxy‐3,5‐dimethylisocoumarin ( 1 ) and tyrosol ( 2 ) were isolated and identified as the phytotoxic constituents. Six analogs of 3,4‐dihydro‐isocoumarin were synthesized and shown to be phytotoxic. The synthesized 3,4‐dihydro‐8‐hydroxy‐3,7‐dimethylisocoumarin and 3,4‐dihydro‐8‐hydroxy‐3,3,7‐trimethylisocoumarin were two‐ to three‐fold more phytotoxic than the naturally occurring 1 in a Lemna paucicostata growth bioassay.CONCLUSION
Synthesis and herbicidal activities of the several new analogs of 1 are reported for the first time. These promising molecules should be used as templates for synthesis and testing of more analogs. © 2017 Society of Chemical Industry 相似文献122.
Solanum spegazzinii Bitt., a wild diploid potato species endemic to Argentina, possesses resistance to adverse biotic and
abiotic agents. Northwestern Argentinean populations grouped according to their morphological variability (G1 = localities
East of the Calchaquí Valley, G2 = Calchaquí Valley and G3 = locality Belén) presented problems in seed set following controlled
crosses. Thus, to evaluate if the morphological variability previously reported was sustained on a genetic basis, three introductions
per group and five plants per introduction were used in controlled crosses (genotypic combinations). These were classified
according to the number of seeds produced per fruit. Pollen-style compatibility relations were studied in those crosses that
did not set seeds or that produced less than 30 seeds each. Within groups, G1 produced seeds normally, whereas hybridization
barriers were found in 71.4% and 50.0% of the combinations within G2 and G3, respectively; on the other hand, from 46.7% to
73.3% of the combinations among groups exhibited similar barriers. Variability in the expression of the sites of pollen tube
inhibition in the style was observed both within and among groups. Speculations are made on the possible hybrid origin of
the populations.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献