Maize heterosis affects the structure and dynamics of indigenous rhizospheric auxins-producing Pseudomonas populations.
A rhizobacterial population of 2430 Pseudomonas isolates, originating from one maize hybrid and from its parents, was screened for auxins production. Four hundred and twelve isolates were found to be auxin producers (aia+), and 27 of them were also part of a previously described PhlD+ sub-population. Interestingly, most part of the aia(+)-PhlD+ isolates came from the hybrid. This finding indicates that heterosis allows an increased colonisation by multi-beneficial PGPR strains. Furthermore, results on the abundance and genetic diversity of aia+ isolates gave evidence that maize root colonisation by aia+ Pseudomonas is an inherited trait regulated by heterosis. In fact, two times more aia+ isolates were obtained from the rhizosphere of the hybrid than from the rhizospheres of the parents, and an amplified rDNA restriction analysis showed that the hybrid increases the genetic diversity of aia+ populations when compared to its parents.
Picard
Christine
C
Dipartimento di Scienze e Tecnologie Agroambientali, Area di Microbiologia, Alma Mater Studiorum - Università di Bologna, Viale Fanin 42-44, 40127 Bologna, Italy. mf4681@mclink.it
Bosco
Marco
M
D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D014644:Genetic Variation; D005838:Genotype; D006823:Hybrid Vigor; D007210:Indoleacetic Acids / Q000378:metabolism; D018517:Plant Roots; D011549:Pseudomonas / Q000235:genetics / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D003313:Zea mays / Q000235:genetics* / Q000382:microbiology*
D004269:DNA, Bacterial; D007210:Indoleacetic Acids; D012336:RNA, Ribosomal, 16S