Auxin Profiling and GmPIN Expression in Phytophthora sojae -Soybean Root Interactions

• Published in: Phytopathology Vol. 110; no. 12; pp. 1988 - 2002
• Main Authors: Stasko, Anna K, Batnini, Amine, Bolanos-Carriel, Carlos, Lin, Jinshan Ella, Lin, Yun, Blakeslee, Joshua J, Dorrance, Anne E
• Format: Journal Article
• Language: English
• Published: United States 01-12-2020
• Subjects: Gene Expression Regulation, Plant; Glycine max; Indoleacetic Acids; Phytophthora; Plant Diseases; Plant Roots; soybean; biochemistry and cell biology; auxin; PIN genes; genetics and resistance; Phytophthora; quantitative disease resistance; roots; metabolite profiling
• ISSN: 0031-949X; 1943-7684
• DOI: 10.1094/PHYTO-02-20-0046-R

Auxin (indole-3-acetic acid, IAA) has been implicated as a susceptibility factor in both beneficial and pathogenic molecular plant-microbe interactions. Previous studies have identified a large number of auxin-related genes underlying quantitative disease resistance loci (QDRLs) for
Thus, we hypothesized that auxin may be involved the
-soybean interaction. The levels of IAA and related metabolites were measured in mycelia and media supernatant as well as in mock and inoculated soybean roots in a time course assay. The expression of 11 soybean
(
) auxin efflux transporter genes was also examined. Tryptophan, an auxin precursor, was detected in the
mycelia and media supernatant. During colonization of roots, levels of IAA and related metabolites were significantly higher in both moderately resistant Conrad and moderately susceptible Sloan inoculated roots compared with mock controls at 48 h postinoculation (hpi) in one experiment and at 72 hpi in a second, with Sloan accumulating higher levels of the auxin catabolite IAA-Ala than Conrad. Additionally, one
at 24 hpi, one at 48 hpi, and three at 72 hpi had higher expression in inoculated compared with the mock control roots in Conrad. The ability of resistant cultivars to cope with auxin accumulation may play an important role in quantitative disease resistance. Levels of jasmonic acid (JA), another plant hormone associated with defense responses, were also higher in inoculated roots at these same time points, suggesting that JA also plays a role during the later stages of infection.