Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.26.9 (ribonuclease)
 6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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.
 ...
PMID: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. 1035 99

Treatment of hypocotyl sections or cell suspension cultures of dwarf French bean (Phaseolus vulgaris L.) with an abiotic elicitor (denatured ribonuclease A) resulted in increased extractable activity of the enzyme l-phenylalanine ammonia-lyase. This induction could be transmitted from treated cells through a dialysis membrane to cells which were not in direct contact with the elicitor. In hypocotyl sections, induction of isoflavonoid phytoalexin accumulation was also transmitted across a dialysis membrane, although levels of insoluble, lignin-like phenolic material remained unchanged in elicitor-treated and control sections. In bean cell suspension cultures, the induction of phenylalanine ammonia-lyase in cells separated from ribonuclease-treated cells by a dialysis membrane was also accompanied by increases in the activities of chalcone synthase and chalcone isomerase, two enzymes previously implicated in the phytoalexin defense response. Such intercellular transmission of elicitation did not occur in experiments with cells treated with a biotic elicitor preparation heat-released from the cell walls of the bean pathogen Colletotrichum lindemuthianum. The results confirm and extend previous suggestions that a low molecular weight, diffusible factor of host plant origin is involved (in French bean) in the intercellular transmission of the elicitation response to abiotic elicitors.
 ...
PMID:Phytoalexin Induction in French Bean : Intercellular Transmission of Elicitation in Cell Suspension Cultures and Hypocotyl Sections of Phaseolus vulgaris. 1666 13

Two dominant alleles of the I locus in Glycine max silence nine chalcone synthase (CHS) genes to inhibit function of the flavonoid pathway in the seed coat. We describe here the intricacies of this naturally occurring silencing mechanism based on results from small RNA gel blots and high-throughput sequencing of small RNA populations. The two dominant alleles of the I locus encompass a 27-kb region containing two perfectly repeated and inverted clusters of three chalcone synthase genes (CHS1, CHS3, and CHS4). This structure silences the expression of all CHS genes, including CHS7 and CHS8, located on other chromosomes. The CHS short interfering RNAs (siRNAs) sequenced support a mechanism by which RNAs transcribed from the CHS inverted repeat form aberrant double-stranded RNAs that become substrates for dicer-like ribonuclease. The resulting primary siRNAs become guides that target the mRNAs of the nonlinked, highly expressed CHS7 and CHS8 genes, followed by subsequent amplification of CHS7 and CHS8 secondary siRNAs by RNA-dependent RNA polymerase. Most remarkably, this silencing mechanism occurs only in one tissue, the seed coat, as shown by the lack of CHS siRNAs in cotyledons and vegetative tissues. Thus, production of the trigger double-stranded RNA that initiates the process occurs in a specific tissue and represents an example of naturally occurring inhibition of a metabolic pathway by siRNAs in one tissue while allowing expression of the pathway and synthesis of valuable secondary metabolites in all other organs/tissues of the plant.
 ...
PMID:Endogenous, tissue-specific short interfering RNAs silence the chalcone synthase gene family in glycine max seed coats. 1982 Jan 89