Diversity of culturable bacteria and occurrence of phytopathogenic species in bean seeds (Phaseolus vulgaris L.) preserved in a germplasm bank
The preservation of plant genetic resources involves the conservation of the microbial biota associated with them. The presence of culturable bacteria in a series of 16 bean seed batches, corresponding to nine local bean varieties, stored in a germplasm bank was studied by amplifying and sequencing the 16S rDNA. Microorganisms identified in seed lots were classified into three groups: environmental biota (present in all samples), biota characteristic of humans and animals (present in 53 % of samples) and phytopathogenic biota (present in 19 % of samples). Genus diversity ranged between 0.6931 and 2.0942 according to the Shannon–Weaver Index (H’), the sample presenting the highest number of plant pathogenic bacteria being the most diverse. This result suggests that contrary to common practice in diagnostic laboratories, it is necessary to identify all culturable bacteria isolates from each sample. In addition, the fact that potentially phytopathogenic bacteria have been preserved in a genebank should emphasize the importance of rigorous sanitary controls for plant genetic resources.
KeywordsBiodiversity indices Curtobacterium flaccumfaciens Germplasm conservation Phaseolus vulgaris Plant pathogenic bacteria
This work was supported by Project INIA-RF2007-00016-C04-03. The Spanish Plant Genetic Resource Center (CRF-INIA) has provided the batches of seeds for this study.
- Chupp Ch, Sherf AF (1960) Vegetable diseases and their control. The Ronald Press Company, New YorkGoogle Scholar
- González AJ, Mendoza MC, Tello JC (2004) Microorganismos patógenos transmitidos por semilla de judía tipo granja asturiana. Saneamiento de semilla. SERIDA/KRK, Oviedo, SpainGoogle Scholar
- Margalef DR (1958) Information theory in ecology. Gen Syst 3:36–71Google Scholar
- Neergaard P (1988) Seed pathology, vol I and II. MacMillan, HoundmillsGoogle Scholar
- Shannon CE, Weaver W (1949) The mathematical theory of communication. University Illinois Press, UrbanaGoogle Scholar