Bacterial population structure and dynamics during the development of almond drupes
Article first published online: 4 MAR 2014
© 2014 The Society for Applied Microbiology This article has been contributed to by US Government employees and their work is in the public domain in the USA
Journal of Applied Microbiology
Volume 116, Issue 6, pages 1543–1552, June 2014
How to Cite
McGarvey, J.A., Connell, J.H., Stanker, L.H. and Hnasko, R. (2014), Bacterial population structure and dynamics during the development of almond drupes. Journal of Applied Microbiology, 116: 1543–1552. doi: 10.1111/jam.12464
- Issue published online: 19 MAY 2014
- Article first published online: 4 MAR 2014
- Accepted manuscript online: 5 FEB 2014 05:01AM EST
- Manuscript Accepted: 29 JAN 2014
- Manuscript Revised: 8 JAN 2014
- Manuscript Received: 8 NOV 2013
- U.S. Department of Agriculture, Agricultural Research Service National Program 108 Food Safety
- microbial structure;
To describe the bacterial populations and their dynamics during the development of almond drupes.
Methods and Results
We examined 16S rRNA gene libraries derived from the bacterial populations on almond drupes at three stages of development: (i) when the drupes were full sized, but before embryo development, (ii) when the drupe hulls first began to split and (iii) when the drupes were fully mature, but before harvesting. Our data revealed that the immature drupes were colonized by relatively few types of bacteria, belonging mostly to common phyllosphere-associated bacteria within the genera Pseudomonas, Pantoea, Methylobacterium and Sphingomonas. However, after the hulls first began to split, the level of bacterial diversity increased and continued to do so until the drupes were fully mature. At the last sampling period, we observed several sequences belonging to bacteria that are not usually associated with the phyllosphere, including some identical to Salmonella enterica.
The bacterial populations on almond drupes before hull split were composed of relatively few types, most of which were commonly associated with the phyllosphere. However, after hull split, the level of microbial diversity increased, which was mostly due to increased levels of bacteria that are not normally associated with the phyllosphere, including Salm. enterica.
Significance and Impact of the Study
This is the first report of the bacterial populations associated with almond drupes and their dynamics during development. Of specific significance is the observation that Salm. enterica was present on the drupes just prior to harvesting, which may represent a critical control point.