Article

Nitrogen deficiency as well as phosphorus deficiency in sorghum promotes the production and exudation of 5-deoxystrigol, the host recognition signal for arbuscular mycorrhizal fungi and root parasites.

Weed Science Center, Utsunomiya University, 350 Mine-Machi, Utsunomiya, Japan.
Planta (impact factor: 3). 01/2008; 227(1):125-32. DOI:10.1007/s00425-007-0600-5
Source: PubMed

ABSTRACT Strigolactones released from plant roots induce hyphal branching of symbiotic arbuscular mycorrhizal (AM) fungi and germination of root parasitic weeds, Striga and Orobanche spp. We already demonstrated that, in red clover plants (Trifolium pratense L.), a host for both AM fungi and the root holoparasitic plant Orobanche minor Sm., reduced supply of phosphorus (P) but not of other elements examined (N, K, Ca, Mg) in the culture medium significantly promoted the secretion of a strigolactone, orobanchol, by the roots of this plant. Here we show that in the case of sorghum [Sorghum bicolor (L.) Moench], a host of both the root hemiparasitic plant Striga hermonthica and AM fungi, N deficiency as well as P deficiency markedly enhanced the secretion of a strigolactone, 5-deoxystrigol. The 5-deoxystrigol content in sorghum root tissues also increased under both N deficiency and P deficiency, comparable to the increase in the root exudates. These results suggest that strigolactones may be rapidly released after their production in the roots. Unlike the situation in the roots, neither N nor P deficiency affected the low content of 5-deoxystrigol in sorghum shoot tissues.

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Keywords

5-deoxystrigol content
 
elements
 
fungi
 
germination
 
low content
 
N deficiency
 
Orobanche spp
 
P deficiency
 
parasitic weeds
 
plant roots induce hyphal branching
 
red clover plants
 
root exudates
 
root hemiparasitic plant Striga hermonthica
 
root holoparasitic plant Orobanche minor Sm
 
secretion
 
sorghum [Sorghum bicolor
 
strigolactone
 
strigolactones
 
symbiotic arbuscular mycorrhizal
 
Trifolium pratense L