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Root System Architecture (root + system_architecture)

Distribution by Scientific Domains
Life Sciences100%

Selected Abstracts

Plant and fungal identity determines pathogen protection of plant roots by arbuscular mycorrhizas

JOURNAL OF ECOLOGY, Issue 6 2009
Benjamin A. Sikes
Summary 1.,A major benefit of the mycorrhizal symbiosis is that it can protect plants from below-ground enemies, such as pathogens. Previous studies have indicated that plant identity (particularly plants that differ in root system architecture) or fungal identity (fungi from different families within the Glomeromycota) can determine the degree of protection from infection by pathogens. Here, we test the combined effects of plant and fungal identity to assess if there is a strong interaction between these two factors. 2.,We paired one of two plants (Setaria glauca, a plant with a finely branched root system and Allium cepa, which has a simple root system) with one of six different fungal species from two families within the Glomeromycota. We assessed the degree to which plant identity, fungal identity and their interaction determined infection by Fusarium oxysporum, a common plant pathogen. 3.,Our results show that the interaction between plant and fungal identity can be an important determinant of root infection by the pathogen. Infection by Fusarium was less severe in Allium (simple root system) or when Setaria (complex root system) was associated with a fungus from the family Glomeraceae. We also detected significant plant growth responses to the treatments; the fine-rooted Setaria benefited more from associating with a member of the family Glomeraceae, while Allium benefited more from associating with a member of the family Gigasporaceae. 4.,Synthesis. This study supports previous claims that plants with complex root systems are more susceptible to infection by pathogens, and that the arbuscular mycorrhizal symbiosis can reduce infection in such plants , provided that the plant is colonized by a mycorrhizal fungus that can offer protection, such as the isolates of Glomus used here. [source]

N -acyl-L-homoserine lactones: a class of bacterial quorum-sensing signals alter post-embryonic root development in Arabidopsis thaliana

PLANT CELL & ENVIRONMENT, Issue 10 2008
RANDY ORTÍZ-CASTRO
ABSTRACT N -acyl-homoserine lactones (AHLs) belong to a class of bacterial quorum-sensing signals important for bacterial cell-to-cell communication. We evaluated Arabidopsis thaliana growth responses to a variety of AHLs ranging from 4 to 14 carbons in length, focusing on alterations in post-embryonic root development as a way to determine the biological activity of these signals. The compounds affected primary root growth, lateral root formation and root hair development, and in particular, N -decanoyl-HL (C10-HL) was found to be the most active AHL in altering root system architecture. Developmental changes elicited by C10-HL were related to altered expression of cell division and differentiation marker lines pPRZ1:uidA, CycB1:uidA and pAtEXP7:uidA in Arabidopsis roots. Although the effects of C10-HL were similar to those produced by auxins in modulating root system architecture, the primary and lateral root response to this compound was found to be independent of auxin signalling. Furthermore, we show that mutant and overexpressor lines for an Arabidopsis fatty acid amide hydrolase gene (AtFAAH) sustained altered growth response to C10-HL. All together, our results suggest that AHLs alter root development in Arabidopsis and that plants posses the enzymatic machinery to metabolize these compounds. [source]

Osmotic regulation of root system architecture

THE PLANT JOURNAL, Issue 1 2005
Karen I. Deak
Summary Although root system architecture is known to be highly plastic and strongly affected by environmental conditions, we have little understanding of the underlying mechanisms controlling root system development. Here we demonstrate that the formation of a lateral root from a lateral root primordium is repressed as water availability is reduced. This osmotic-responsive regulatory mechanism requires abscisic acid (ABA) and a newly identified gene, LRD2. Mutant analysis also revealed interactions of ABA and LRD2 with auxin signaling. Surprisingly, further examination revealed that both ABA and LRD2 control root system architecture even in the absence of osmotic stress. This suggests that the same molecules that mediate responses to environmental cues can also be regulators of intrinsic developmental programs in the root system. [source]