The Bacterial Pathogen Xanthomonas oryzae Overcomes Rice Defenses by Regulating Host Copper Redistribution  

Abstract

Pathogen effectors are virulence factors causing plant diseases. How the host targets of these effectors facilitate pathogen infection is largely unknown. An effector of Xanthomonas oryzae pv oryzae (Xoo) transcriptionally activates rice (Oryza sativa) susceptibility gene Xa13 to cause bacterial blight disease. Xa13 encodes an indispensable plasma membrane protein of the MtN3/saliva family, which is prevalent in eukaryotes with unknown biochemical function. We show that the XA13 protein cooperates with two other proteins, COPT1 and COPT5, to promote removal of copper from xylem vessels, where Xoo multiplies and spreads to cause disease. Copper, an essential micronutrient of plants and an important element for a number of pesticides in agriculture, suppresses Xoo growth. Xoo strain PXO99 is more sensitive to copper than other strains; its infection of rice is associated with activation of XA13, COPT1, and COPT5, which modulate copper redistribution in rice. The involvement of XA13 in copper redistribution has led us to propose a mechanism of bacterial virulence.

A genome-wide analysis of SWEET gene family in cotton and their expressions under different stresses

“…Some SWEETs showed higher expression levels in reproductive tissues especially in floral organs, such as SWEET1a_At/Dt (petals, sepals, and 10-25 DPA fibers), SWEET1b_At/Dt (stamen, − 1 DPA ovule, 1DPA and 5DPA seeds, 10 DPA fiber), SWEET2a_At/Dt (petals and stamens), SWEET7a_At/Dt (petals and stamens). The results indicated that SWEETs also involved in the reproductive development of cotton, consistent with the results in Arabidopsis and rice (Yuan et al 2009;Yuan et al 2010;Guan et al 2008;Sun et al 2013;Liu et al 2011;Ge et al 2000). In addition, SWEET2a_At/Dt, SWEET1b_Dt and SWEET4_At were detected with high expression levels in germinating seed, cotyledons and roots during germination (Fig.…”

“…Suppression of OsSWEET11 resulted in pollen dysplasia, leading to male infertility (Yuan et al 2009;Liu et al 2011;Ge et al 2000). AtSWEET5 was highly expressed in the female gametophyte during the three-cell pollen stage (Yuan et al 2010). Some researches have showed that SWEETs plays a role in the process of plant senescence and response to abiotic stresses.…”

“…AtSWEET13 is involved in the regulation of aluminum ion balance in plants (Zhao et al 2009). OsSWEET11 forms a complex with two other copper transporter protein COPT1 and COPT5 in the plasma membrane (Yuan et al 2009;Yuan et al 2010), regulating the transport of copper ions and sugars (Yuan et al 2010).…”

Rice xa13 Recessive Resistance to Bacterial Blight Is Defeated by Induction of the Disease Susceptibility Gene Os-11N3

“…within the host (Yuan et al, 2010). Another report indicates that N3 proteins, including Os-8N3 and Os-11N3, can function as low-affinity glucose transporters, allowing ingress or efflux of glucose into or out of cells according to the glucose concentration gradient.…”

Function and Regulation of the Plant COPT Family of High-Affinity Copper Transport Proteins

“…Consequently, Cu is essential for fundamental biological processes in plants including photosynthesis, mitochondrial respiration, oxidative stress protection, cell wall metabolism, ethylene perception, response to pathogens, and molybdenum cofactor biosynthesis [1][2][3]. The optimal endogenous Cu levels in plants can substantially range depending on the species and its environmental availability.…”