Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2004-1-20
pubmed:abstractText
Many plants contain latex that exudes when leaves are damaged, and a number of proteins and enzymes have been found in it. The roles of those latex proteins and enzymes are as yet poorly understood. We found that papain, a cysteine protease in latex of the Papaya tree (Carica papaya, Caricaceae), is a crucial factor in the defense of the papaya tree against lepidopteran larvae such as oligophagous Samia ricini (Saturniidae) and two notorious polyphagous pests, Mamestra brassicae (Noctuidae) and Spodoptera litura (Noctuidae). Leaves of a number of laticiferous plants, including papaya and a wild fig, Ficus virgata (Moraceae), showed strong toxicity and growth inhibition against lepidopteran larvae, though no apparent toxic factors from these species have been reported. When the latex was washed off, the leaves of these lactiferous plants lost toxicity. Latexes of both papaya and the wild fig were rich in cysteine-protease activity. E-64, a cysteine protease-specific inhibitor, completely deprived the leaves of toxicity when painted on the surface of papaya and fig leaves. Cysteine proteases, such as papain, ficin, and bromelain, all showed toxicity. The results suggest that plant latex and the proteins in it, cysteine proteases in particular, provide plants with a general defense mechanism against herbivorous insects.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0960-7412
pubmed:author
pubmed:issnType
Print
pubmed:volume
37
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
370-8
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Papain protects papaya trees from herbivorous insects: role of cysteine proteases in latex.
pubmed:affiliation
National Institute of Agrobiological Sciences, 1-2 Ohwashi, Tsukuba, Ibaraki 305-8634, Japan.,
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't