caa a22 4500 606208429 CHVBK 20210128101022.0 cr unu---uuuuu 210128e20151101xx s 000 0 eng 10.1007/s00425-015-2346-9 doi (NATIONALLICENCE)springer-10.1007/s00425-015-2346-9 Zebra chip disease decreases tuber ( Solanum tuberosum L.) protein content by attenuating protease inhibitor levels and increasing protease activities [Elektronische Daten] [G. Kumar, Lisa Knowles, N. Knowles] Main conclusion : Zebra chip disease of potato decreases protease inhibitor levels resulting in enhanced serine-type protease activity, decreased protein content and altered protein profiles of fully mature tubers. Zebra-chip (ZC), caused by Candidatus Liberibacter solanacearum (CLso), is a relatively new disease of potato that negatively affects growth, yield, propagation potential, and fresh and process qualities of tubers. Diseased plants produce tubers with characteristic brown discoloration of vascular tissue accompanied by elevated levels of free amino acids and reducing sugars. Here we demonstrate that ZC disease induces selective protein catabolism in tubers through modulating protease inhibitor levels. Soluble protein content of tubers from CLso-infected plants was 33% lower than from non-infected plants and electrophoretic analyses revealed substantial reductions in major tuber proteins. Patatin (~40kDa) and ser-, asp- (22kDa) and cys-type (85kDa) protease inhibitors were either absent or greatly reduced in ZC-afflicted tubers. In contrast to healthy (non-infected) tubers, the proteolytic activity in CLso infected tubers was high and the ability of extracts from infected tubers to inhibit trypsin (ser-type) and papain (cys-type) proteases greatly attenuated. Moreover, extracts from CLso-infected tubers rapidly catabolized proteins purified from healthy tubers (40kDa patatin, 22kDa protease inhibitors, 85kDa potato multicystatin) when subjected to proteolysis individually. In contrast, crude extracts from non-infected tubers effectively inhibited the proteolytic activity from ZC-afflicted tubers. These results suggest that the altered protein profile of ZC afflicted tubers is largely due to loss of ser- and cys-type protease inhibitors. Further analysis revealed a novel PMSF-sensitive (ser) protease (ca. 80-120kDa) in CLso infected tubers. PMSF abolished the proteolytic activities responsible for degrading patatin, the 22kDa protease inhibitor(s) and potato multicystatin by CLso infected tubers. The disease-induced loss of patatin and protease inhibitors therefore appears to be modulated by ser-type protease(s). The selective catabolism of proteins in ZC-afflicted tubers undoubtedly affects downstream aspects of carbohydrate and amino acid metabolism, which is ultimately reflected by the accumulation of reducing sugars, free amino acids and reduced sprouting capacity. Springer-Verlag Berlin Heidelberg, 2015 Solanum tuberosum nationallicence Zebra chip disease nationallicence Candidatus Liberibacter solanacearum nationallicence Tuber protein nationallicence Patatin nationallicence Protease inhibitors nationallicence Potato multicystatin nationallicence Kunitz nationallicence Amino acids nationallicence Proteolysis nationallicence ANOVA : Analysis of variance nationallicence asp : Aspartic nationallicence BAPNA : N α-benzoyl-l-arginine 4-nitroanilide hydrochloride nationallicence cys : Cysteine nationallicence Pep : Pepstatin nationallicence PIN I : Potato protease inhibitor I nationallicence PIN II : Potato protease inhibitor II nationallicence PKPI : Potato Kunitz-type protease inhibitor nationallicence PMC : Potato multicystatin nationallicence ser : Serine nationallicence ZC : Zebra chip nationallicence Kumar G. Postharvest Physiology and Biochemistry Laboratory, Department of Horticulture, Washington State University, P.O. Box 646414, 99164-6414, Pullman, WA, USA aut Knowles Lisa Postharvest Physiology and Biochemistry Laboratory, Department of Horticulture, Washington State University, P.O. Box 646414, 99164-6414, Pullman, WA, USA aut Knowles N. Postharvest Physiology and Biochemistry Laboratory, Department of Horticulture, Washington State University, P.O. Box 646414, 99164-6414, Pullman, WA, USA aut Planta Springer Berlin Heidelberg 242/5(2015-11-01), 1153-1166 0032-0935 242:5<1153 2015 242 425 https://doi.org/10.1007/s00425-015-2346-9 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00425-015-2346-9 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kumar G. Postharvest Physiology and Biochemistry Laboratory, Department of Horticulture, Washington State University, P.O. Box 646414, 99164-6414, Pullman, WA, USA aut NATIONALLICENCE 700 1- Knowles Lisa Postharvest Physiology and Biochemistry Laboratory, Department of Horticulture, Washington State University, P.O. Box 646414, 99164-6414, Pullman, WA, USA aut NATIONALLICENCE 700 1- Knowles N. Postharvest Physiology and Biochemistry Laboratory, Department of Horticulture, Washington State University, P.O. Box 646414, 99164-6414, Pullman, WA, USA aut NATIONALLICENCE 773 0- Planta Springer Berlin Heidelberg 242/5(2015-11-01), 1153-1166 0032-0935 242:5<1153 2015 242 425