Helminthosporium maydis T toxin decreased calcium transport into mitochondria of susceptible corn

Journal Article · Sun Apr 01 04:00:00 EST 1984 · Plant Physiol.; (United States)

DOI:https://doi.org/10.1104/pp.74.4.804· OSTI ID:7096930

Kimber, A; Sze, H

The effects of purified Helminthosporium maydis T (HmT) toxin on active Ca/sup 2 +/ transport into isolated mitochondria and microsomal vesicles were compared for a susceptible (T) and a resistant (N) strain of corn (Zea mays). ATP, malate, NADH, or succinate could drive /sup 45/Ca/sup 2 +/ transport into mitochondria of corn roots. Ca/sup 2 +/ uptake was dependent on the proton electrochemical gradient generated by the redox substrates or the reversible ATP synthetase, as oligomycin inhibited ATP-driven CA/sup 2 +/ uptake while KCN inhibited transport driven by the redox substrates. Purified native HmT toxin completely inhibited Ca/sup 2 +/ transport into T mitochondria at 5 to 10 nanograms per milliliter while transport into N mitochondria was decreased slightly by 100 nanograms per milliliter toxin. Malate-driven Ca/sup 2 +/ transport in T mitochondria was frequently more inhibited by 5 nanograms per milliliter toxin than succinate or ATP-driven Ca/sup 2 +/ uptake. However, ATP-dependent Ca/sup 2 +/ uptake into microsomal vesicles from either N or T corn was not inhibited by 100 nanograms per milliliter toxin. Similarly, toxin had no effect on proton gradient formation ((/sup 14/C)methylamine accumulation) in microsomal vesicles. These results show that mitochondrial and not microsomal membrane is a primary site of HmT toxin action. HmT toxin may inhibit formation of or dissipate the electrochemical proton gradient generated by substrate-driven electron transport or the mitochondrial ATPase, after interacting with a component(s) of the mitochondrial membrane in susceptible corn.

• Research Organization: Univ. of Kansas, Lawrence
• DOE Contract Number: AS05-82ER13015
• OSTI ID: 7096930
• Journal Information: Plant Physiol.; (United States), Journal Name: Plant Physiol.; (United States) Vol. 74:4; ISSN PLPHA
• Country of Publication: United States
• Language: English

Related Subjects

550901* -- Pathology-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACID ANHYDRASES
ALKALINE EARTH METALS
ATP-ASE
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
CALCIUM
CARBON 14
CARBON ISOTOPES
CELL CONSTITUENTS
CEREALS
DISEASES
ELEMENTS
ENZYME ACTIVITY
ENZYMES
EVEN-EVEN NUCLEI
FUNGAL DISEASES
FUNGI
GRAMINEAE
GRASS
HYDROLASES
INFECTIOUS DISEASES
ISOTOPE APPLICATIONS
ISOTOPES
LABELLING
LIGHT NUCLEI
MAIZE
METALS
MINERAL CYCLING
MITOCHONDRIA
NUCLEI
ORGANOIDS
PHOSPHOHYDROLASES
PLANTS
RADIOISOTOPES
TRACER TECHNIQUES
UPTAKE
YEARS LIVING RADIOISOTOPES