The type of irrigation system can influence the risk of crop contamination: overhead irrigation, for instance, is more likely to produce virus contamination than are furrow and drip irrigation [13]. Studies conducted in California found no significant differences in coliform counts among crops spray-irrigated Rabusertib supplier with two types of treated wastewater or with well water. This was found despite the fact that the treated waters used in this study showed higher levels of total and fecal coliforms than the well water [14]. The overall impact of using surface water

for direct crop applications on fruit surface bacterial communities has not been reported to date. Denaturing gradient gel electrophoresis studies have indicated that variables such as plant species and stage

of development can affect the composition of phyllosphere microbial communities. In addition, it was found that these communities are far more complex than culture-based methods used in the past had indicated [6, 15, 16]. Recent studies described learn more the bacterial diversity of phyllosphere samples from natural and agricultural ecosystems using traditional cloning and sequencing approaches, leading to the identification of many previously undescribed members of these communities. These studies also indicated that phyllosphere communities can be Enzalutamide order altered by the application of diverse agricultural materials [16–18]. More recently next-generation sequencing technologies, including 454-pyrosequencing, have provided more comprehensive descriptions of bacterial diglyceride communities in different environments due to the increased number of sequence reads obtained [19–26]. A study of bacterial diversity on tree leaves using 454 sequencing indicated that tree and bacterial community phylogeny are associated, and that the geographic differentiation of bacterial communities on a single tree species is minimal [27]. To our knowledge, no such studies have been conducted to date to describe the impact of water quality on bacterial populations in

the phyllosphere of specialty crops. We utilized 454-pyrosequencing to generate 34,016 16S rRNA gene sequences from 16 field samples: 10 tomato fruit samples that had been sprayed with either surface water (ps), or groundwater (pg), three samples of surface water (ws), and three samples of groundwater (wg). Using these data, we sought to 1) compare the bacterial profile of ground and surface water that was used for pesticide applications and 2) assess the impact of water quality on the fruit surface bacterial profile of a tomato crop. A smaller preliminary dataset of 2008 fruit surface samples generated through Sanger sequencing is also included for comparison. Despite the significant differences between bacterial communities in surface and groundwater, the surface communities on the tomato fruits treated with these water sources could not be differentiated by a variety of statistical methods.