M. Redondo-nieto et al., Boron deficiency affects early infection events in the pea-Rhizobium symbiotic interaction, AUST J PLAN, 28(8), 2001, pp. 819-823
The effects of the deprivation of boron (B) on Rhizobium-legume signaling a
nd preinfection events have been investigated in pea (Pisum sativum L. cv.
Argona). The capacity of root exudates to induce the activity of nodulation
genes was modulated by B nutrition in the host plant. Exudates derived fro
m B-deficient pea plants led to a low level of nod-gene expression that cou
ld be correlated with poor root hair curling. However, inoculation of B-def
icient plants with bacteria grown in the presence of the nod-gene inducing
hesperetin, restored root hair curling. The attachment of bacteria to roots
was also diminished in plants grown in the absence of the micronutrient, a
nd it was not recovered by hesperetin. Both phenomena provoked a reduction
in nodulation of more than 50%. Furthermore, infection thread development w
as arrested at very early stages, and cell invasion by endocytosis was prec
luded, leading to almost empty of bacteria B-deficient nodules.