Improved Phytophthora resistance in commercial chickpea (Cicer arietinum) varieties negatively impacts symbiotic gene signalling and symbiotic potential in some varieties.
Breeding disease-resistant varieties is one of the most effective and economical means to combat soilborne diseases in pulse crops. Commonalities between pathogenic and mutualistic microbe colonization strategies, however, raises the concern that reduced susceptibility to pathogens may simultaneously reduce colonization by beneficial microbes. We investigate here the degree of overlap in the transcriptional response of the Phytophthora medicaginis susceptible chickpea variety 'Sonali' to the early colonization stages of either Phytophthora, rhizobial bacteria or arbuscular mycorrhizal fungi. From a total of 6476 genes differentially expressed in Sonali roots during colonization by any of the microbes tested, 10.2% were regulated in a similar manner regardless of whether it was the pathogenic oomycete or a mutualistic microbe colonizing the roots. Of these genes, 49.7% were oppositely regulated under the same conditions in the moderately Phytophthora resistant chickpea variety 'PBA HatTrick'. Chickpea varieties with improved resistance to Phytophthora also displayed lower colonization by rhizobial bacteria and mycorrhizal fungi leading to an increased reliance on N and P from soil. Together, our results suggest that marker-based breeding in crops such as chickpea should be further investigated such that plant disease resistance can be tailored to a specific pathogen without affecting mutualistic plant:microbe interactions.
Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, New South Wales, Australia, 2753.
Jonathan M
JM
Plett
Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, New South Wales, Australia, 2753.
Krista L
KL
Plett
New South Wales Department of Primary Industries, Tamworth, New South Wales, Australia, 2340.
Sean L
SL
Bithell
Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, New South Wales, Australia, 2753.
Chris
C
Mitchell
New South Wales Department of Primary Industries, Tamworth, New South Wales, Australia, 2340.
Kevin
K
Moore
Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, New South Wales, Australia, 2753.
Jeff R
JR
Powell
Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, New South Wales, Australia, 2753.
Ian C
IC
Anderson
D029863:Cicer / Q000235:genetics / Q000378:metabolism / Q000382:microbiology*; D060467:Disease Resistance; D017343:Genes, Plant; D054884:Host-Pathogen Interactions; D059128:Mesorhizobium / Q000502:physiology*; D038821:Mycorrhizae / Q000502:physiology*; D009584:Nitrogen / Q000378:metabolism; D009586:Nitrogen Fixation; D010838:Phytophthora / Q000502:physiology*; D010935:Plant Diseases; D018515:Plant Leaves / Q000378:metabolism; D055170:Plant Root Nodulation; D013559:Symbiosis
D009584:Nitrogen
Phytophthora root rot; arbuscular mycorrhizal fungi; crop breeding; disease resistance; mutualism; pathogenesis; plant: microbe interaction; rhizobial bacteria; transcriptomics