This paper reports a highly economical and accessible approach to generate different discrete relative humidity conditions in spatially separated wells of a modified multi-well plate for humidity assay of plant-pathogen interactions with good throughput. We demonstrated that a discrete humidity gradient could be formed within a few minutes and maintained over a period of a few days inside the d...

Three damaging soybean diseases, Sclerotinia stem rot caused by a fungus sclerotiorum (Lid.) de Bary, Phytophthora root sojae, and cyst nematode (Heterodera glycines Ichinohe), are destructive to growth yield cause huge economic losses. Biocontrol is an effective way control diseases with the advantage of being environmentally friendly sustainable. To date, few reviews have reported these three...

Soybean (Glycine max L. Merr.) is a versatile and important agronomic crop grown worldwide. Each year millions of dollars of potential yield revenues are lost due to a root rot disease caused by the oomycete Phytophthora sojae (Kaufmann & Gerdemann). Since the root is the primary site of infection by this organism, we undertook an examination of the physicochemical barriers in soybean root, nam...

Oomycete pathogens produce a large number of effectors to promote infection. Their mode of action are largely unknown. Here we show that a Phytophthora sojae effector, PsCRN63, suppresses flg22-induced expression of FRK1 gene, a molecular marker in pathogen-associated molecular patterns (PAMP)-triggered immunity (PTI). However, PsCRN63 does not suppress upstream signaling events including flg22...

A series of single genes protect soybean from the root and stem disease caused by the oomycete pathogen Phytophthora sojae. In the last two decades, Rps1-k has been the most stable and widely used Phytophthora resistance gene for the major soybean-producing regions of the United States. Four highly similar genes encoding coiled coil-nucleotide binding-leucine rich repeat (CC-NB-LRR)-type protei...

In 1990, new Phytophthora strains, later recognized as a species, sansomeana, were found to cause root rot (PRR) in soybean addition P. sojae. The emergence and spread of second pathogen causing PRR poses significant threat production. While genetic resistance sojae has been developed widely deployed management tool, these varieties appear largely ineffective at controlling which broad host-ran...

Plant pathogens secrete an arsenal of effector proteins to impair host immunity. Some effectors possess enzymatic activities that can modify their host targets. Previously, we demonstrated that a Phytophthora sojae RXLR effector Avr3b acts as a Nudix hydrolase when expressed in planta; and this enzymatic activity is required for full virulence of P. sojae strain P6497 in soybean (Glycine max). ...

Resistance of soybean against the oomycete pathogen Phytophthora sojae is conferred by a series of Rps genes. We have characterized a disease resistance gene-like sequence NBSRps4/6 that was introgressed into soybean lines along with Rps4 or Rps6. High-resolution genetic mapping established that NBSRps4/6 cosegregates with Rps4. Two mutants, M1 and M2, showing rearrangements in the NBSRps4/6 re...

Polyamines are ubiquitous biologically active aliphatic cations that are at least transiently available in the soil from decaying organic matter. Our objectives in this study were to characterize polyamine uptake kinetics in Phytophthora sojae zoospores and to quantify endogenous polyamines in hyphae, zoospores, and soybean roots. Zoospores contained 10 times more free putrescine than spermidin...