cDNA Cloning of a Sorghum Pathogenesis-Related Protein (PR-10) and Differential Expression of Defense-Related Genes Following Inoculation with Cochliobolus heterostrophus or Colletotrichum sublineolum

Abstract

A sorghum cDNA clone was isolated by differential screening of a cDNA library prepared from mesocotyls (cultivar DK18) inoculated with fungal pathogenes. The deduced translation product shows sequence similarity to a family of intracellular pathogenesis-related proteins (PR-10) with a potential ribonuclease function. We studied the accumulation of PR-10 and chalcone synthase (CHS) transcripts in mesocotyls following inoculation with Cochliobolus heterostrophus or Colletotrichum sublineolum. CHS is involved in phytoalexin synthesis in sorghum. Coordinate expression of PR-10 and CHS genes was localized in the area of inoculation along with the accumulation of phytoalexins. C. heterostrophus is a nonpathogen of sorghum and cytological studies indicated that cultivar DK18 is resistant to C. sublineolum, a sorghum pathogen. We demonstrated that the two fungi triggered different time courses of plant defense reactions. Inoculation with C. heterostrophus resulted in rapid accumulation of PR-10 and CHS transcripts after appressoria had become mature. Accumulation of these transcripts was delayed in plants inoculated with C. sublineolum until penetration of host tissue had been completed and infection vesicles had formed. Results suggest that different recognition events are involved in the expression of resistance to the two fungi used or that C. sublineolum suppresses the nonspecific induction of defense responses.

Synthetic Plant Promoters Containing Defined Regulatory Elements Provide Novel Insights into Pathogen- and Wound-Induced Signaling

“…During compatible interactions, the synthetic promoters accurately report the in vivo situation in which gene activation is slower and perhaps weaker (Lo et al, 1999). In this context, the observed high-level expression of the synthetic promoters during the compatible interaction with a powdery mildew (E. cichoracearum) illustrates their potential usefulness during plant-pathogen interactions of commercial importance.…”

Identification of genes expressed during the compatible interaction of grapevine with Plasmopara viticola through suppression subtractive hybridization (SSH)

“…A strong induction of PR-10 was observed at 12 hpi which is in agreement with a number of other studies that found transcript accumulation of PR-10 in the susceptible grapevine cv. Riesling 12 hpi with P. viticola (Kortekamp 2006), in rice within 12 hpi with Magnaporthe grisea (McGee et al 2001) and in sorghum, inducible PR-10 transcripts reached a maximum level at 12 hpi (Lo et al 1999). When taking these results into account, the induction of PR-10 may play an important role in the defence of grapevine against P. viticola.…”

Requirement of the Cytosolic Interaction between PATHOGENESIS-RELATED PROTEIN10 and LEUCINE-RICH REPEAT PROTEIN1 for Cell Death and Defense Signaling in Pepper

“…More recently, a positive transcription factor, WRKYb, was demonstrated to bind the PR10 promoter and activate the defense signaling pathway in pepper (Lim et al, 2011). Several PR10 family genes were isolated from various plant species, including apple (Malus domestica), asparagus (Asparagus officinalis), parsley (Petroselinum crispum), bean (Phaseolus vulgaris), pea (Pisum sativum), sorghum (Sorghum bicolor), potato (Solanum tuberosum), pepper, and rice (Oryza sativa) (Somssich et al, 1986;Matton and Brisson, 1989;Walter et al, 1990;Warner et al, 1992;Lo et al, 1999;Pü hringer et al, 2000;Park et al, 2004;Hashimoto et al, 2004). The PR10 genes are induced by microbial attack (Somssich et al, 1986), fungal elicitors (Somssich et al, 1986;Walter et al, 1990), or wounding stress (Warner et al, 1992).…”