Aspartic proteinases are expressed in pitchers of the carnivorous plant Nepenthes alata Blanco

An, Chung-Il; Fukusaki, Eiichiro; Kobayashi, Akio

doi:10.1007/s004250100665

Cited by 68 publications

(64 citation statements)

References 29 publications

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“…Cluster roots of H. undulata exude acid phosphatases (20), and evidence for root-secreted proteases has been recently reported in several crop and wild species (21). Digestive glands of carnivorous plant Nepenthes alata also are known to secrete aspartic proteinases into the liquid of the pitcher (22). Our results confirm the notion that cluster roots of Hakea are active in enzyme exudation (20,23) and show that exudation of enzymes is not restricted to cluster roots.…”

Section: Discussionsupporting

confidence: 79%

Plants can use protein as a nitrogen source without assistance from other organisms

Paungfoo‐Lonhienne

Lonhienne²,

Rentsch³

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

306

208

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Nitrogen is quantitatively the most important nutrient that plants acquire from the soil. It is well established that plant roots take up nitrogen compounds of low molecular mass, including ammonium, nitrate, and amino acids. However, in the soil of natural ecosystems, nitrogen occurs predominantly as proteins. This complex organic form of nitrogen is considered to be not directly available to plants. We examined the long-held view that plants depend on specialized symbioses with fungi (mycorrhizas) to access soil protein and studied the woody heathland plant Hakea actites and the herbaceous model plant Arabidopsis thaliana, which do not form mycorrhizas. We show that both species can use protein as a nitrogen source for growth without assistance from other organisms. We identified two mechanisms by which roots access protein.Roots exude proteolytic enzymes that digest protein at the root surface and possibly in the apoplast of the root cortex. Intact protein also was taken up into root cells most likely via endocytosis. These findings change our view of the spectrum of nitrogen sources that plants can access and challenge the current paradigm that plants rely on microbes and soil fauna for the breakdown of organic matter.nitrogen uptake ͉ organic nitrogen ͉ plant nutrition ͉ plant roots ͉ soil protein

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Section: Discussionsupporting

confidence: 79%

Plants can use protein as a nitrogen source without assistance from other organisms

Paungfoo‐Lonhienne

Lonhienne²,

Rentsch³

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

306

208

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“…In this fragmentation, two peptide bonds (Tyr 16 -Leu 17 and Phe 24 -Phe 25 ) were specifically cleaved. These cleavage sites are similar to those of aspartic proteinases (APs) from N. distillatoria (Athauda et al 1998), cardoon (Verı´ssimo et al 1998), wheat (Bleukx et al 1998), and barley (Kervinen et al 1993), suggesting that the peptide bonds were cleaved by AP(s) in the pitcher fluid of N. alata (the presence of AP activity in the pitcher fluid of N. alata is described elsewhere: An et al 2002). Amino acid analysis of the degradation products revealed that alanine, leucine, and tyrosine were released after 1, 3, and 12 h of incubation, respectively (Fig.…”

Section: Discussionmentioning

confidence: 83%

Degradation of a peptide in pitcher fluid of the carnivorous plant Nepenthes alata Blanco

Takekawa

Okazawa

et al. 2002

Planta

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Carnivorous plants acquire substantial amounts of nitrogen from insects. The tropical carnivorous plant Nepenthes produces trapping organs called pitchers at the tips of tendrils elongated from leaf ends. Acidic fluid is secreted at the bottoms of the pitchers. The pitcher fluid includes several hydrolytic enzymes, and some, such as aspartic proteinase, are thought to be involved in nitrogen acquisition from insect proteins. To understand the nitrogen-acquisition process, it is essential to identify the protein-degradation products in the pitcher fluid. To gain insight into protein degradation in pitcher fluid, we used the oxidized B-chain of bovine insulin as a model substrate, and its degradation by the pitcher fluid of N. alata was investigated using liquid chromatography-mass spectrometry (LC-MS). LC-MS analysis of the degradation products revealed that the oxidized B-chain of bovine insulin was initially cleaved at aromatic amino acids such as phenylalanine and tyrosine. These cleavage sites are similar to those of aspartic proteinases from other plants and animals. The presence of a series of peptide fragments as degradation products suggests that exopeptidase(s) is also present in the pitcher fluid. Amino acid analysis and peptide fragment analysis of the degradation products demonstrated that three amino acids plus small peptides were released from the oxidized B-chain of bovine insulin, suggesting that insect proteins are readily degraded to small peptides and amino acids in the pitcher fluid of N. alata.

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“…The slippery walls also prevent the prey from escaping and it eventually drowns in the fluid in zone 3 ( Fig. 1) containing digestive solutions and absorptive glands (Schulze et al 1997;An et al 2002aAn et al , 2002b.…”

Section: Introductionmentioning

confidence: 98%

Slippery surfaces of carnivorous plants: composition of epicuticular wax crystals in Nepenthes alata Blanco pitchers

Riedel

Eichner

Jetter

2003

Planta

113

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Plants in the genus Nepenthes obtain a substantial nutrient supply by trapping insects in highly modified leaves. A broad zone of the inner surface of these pitchers is densely covered with wax crystals on which most insects lose their footing. This slippery wax surface, capturing prey and preventing its escape from the trap, plays a pivotal role in the carnivorous syndrome. To understand the mechanism of slipperiness, the present investigation aimed at an ultrastructural and physico-chemical characterization of the wax crystals in pitchers of N. alata Blanco. Scanning electron microscopy revealed that entire platelets protruded perpendicularly from the surface. Methods were developed that allowed the mechanical removal of wax crystals from the pitcher surface. It could be shown that the sampling was selective for the epicuticular wax, relevant for plant-insect interactions. The crystals consisted of a mixture of aliphatic compounds dominated by very-long-chain aldehydes. Triacontanal, at 43% the most abundant constituent, was largely responsible for crystal formation. Solubility data indicate that the Nepenthes crystals contained polymeric forms of this aldehyde. The resulting mechanical properties of the polymer crystals and the mechanism of slipperiness are discussed.

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Aspartic proteinases are expressed in pitchers of the carnivorous plant Nepenthes alata Blanco

Cited by 68 publications

References 29 publications

Plants can use protein as a nitrogen source without assistance from other organisms

Plants can use protein as a nitrogen source without assistance from other organisms

Degradation of a peptide in pitcher fluid of the carnivorous plant Nepenthes alata Blanco

Slippery surfaces of carnivorous plants: composition of epicuticular wax crystals in Nepenthes alata Blanco pitchers

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