Table 1.

Bacterial species abundance based on plant type and production system (conventional or organic).

	Tissue type	Relative abundance	Relative abundance	P-value
		Conventional	Organic
Tomato	Shoot	0.06	0.13	0.04
	Root	0.02	0.08	<0.001
	Seed	0.03	0.01	0.66
	Total	0.11	0.22	<0.01
Corn	Shoot	0.03	0.1	<0.01
	Root	0.02	0.08	<0.001
	Seed	0.01	0.02	0.4
	Total	0.06	0.2	<0.001
Melon	Shoot	0.09	0.15	0.1
	Root	0.01	0.1	<0.001
	Seed	0	0	Na
	Total	0.1	0.25	<0.001
Pepper	Shoot	0.02	0.04	0.08
	Root	0	0.01	Na
	Seed	0	0.01	Na
	Total	0.02	0.05	0.03

Frequency is shown based on the number of times individual bacteria were cultured from shoot, root or seed tissues in each crop species: tomato, corn, melon, or pepper. P-value was calculated using the Mann-Whitney pairwise post hoc test (PAST version 3.05, University of Oslo, Oslo, Norway). A statistical comparison was not possible when no bacteria species were isolated from individual tissues, and this is noted with na = not applicable. The number of species assessed in this experiment for each tissue type is 32 and the assessment was done from five replicates of each plant species.