United States Department of Agriculture, Agricultural Research Service, Department of Agronomy, Oklahoma State University, Stillwater, Oklahoma 74078.
Plant Physiol. 1982 Apr;69(4):789-92. doi: 10.1104/pp.69.4.789.
Ethylene can induce abscission of leaves and other plant organs. Increased ethylene production by plant tissues can occur after invasion by microorganisms. The fungus Cercospora arachidicola Hori, attacks peanut leaflets and causes defoliation. Our objective was to determine if ethylene was involved in this defoliation. Leaves of three peanut, Arachis sp., genotypes were inoculated with C. arachidicola. Two genotypes, ;Tamnut 74' and PI 109839, produced ethylene and were defoliated. The third genotype, PI 276233, a wild species, did not produce ethylene above control levels and was not defoliated. Increase in ethylene production by Tamnut 74 and PI 109839 coincided with appearance of disease symptoms. Tamnut 74 produced the most ethylene, but PI 109839 was equally defoliated. Thus, less overall ethylene production did not necessarily indicate a more resistant genotype in this system unless ethylene production remained at control levels, as it did for PI 276233. Ethylene sufficient to initiate abscission could have been produced by the seventh day after inoculation when it was similar for both Tamnut 74 and PI 109839, but 3 to 4 times control amounts. This occurred before the rapid increase in ethylene production and before disease symptoms were visible. Silver ion, a potent inhibitor of ethylene action, was sprayed at three concentrations on intact Tamnut 74 plants. All rates reduced abscission and 150 mg/liter Ag(I) decreased abscission to below 10%. The data indicate that ethylene produced by peanut leaves in response to C. arachidicola infection initiates abscission and that ethylene action can be blocked by Ag(I) in such a host-pathogen interaction.
乙烯能诱导叶片和其他植物器官脱落。植物组织中乙烯的产生增加可能发生在微生物入侵之后。真菌 Cercospora arachidicola Hori 攻击花生小叶并导致落叶。我们的目的是确定乙烯是否参与了这种落叶。用 C. arachidicola 接种三种花生，Arachis sp.，基因型的叶片。两个基因型，“Tamnut 74'和 PI 109839，产生乙烯并落叶。第三个基因型，PI 276233，一种野生种，没有产生高于对照水平的乙烯，也没有落叶。Tamnut 74 和 PI 109839 中乙烯产量的增加与疾病症状的出现同时发生。Tamnut 74 产生的乙烯最多，但 PI 109839 同样落叶。因此，在这个系统中，较少的整体乙烯产生并不一定表明基因型更具抗性，除非乙烯产生仍保持在对照水平，就像 PI 276233 一样。足以启动脱落的乙烯可能在接种后第七天产生，此时 Tamnut 74 和 PI 109839 相似，但为对照量的 3 到 4 倍。这发生在乙烯产量快速增加之前，在疾病症状可见之前。银离子是乙烯作用的一种有效抑制剂，被喷洒在完整的 Tamnut 74 植株上，浓度为三种。所有的浓度都减少了脱落，而 150 毫克/升的 Ag（I）将脱落减少到 10%以下。数据表明，花生叶片对 C. arachidicola 感染的反应产生的乙烯启动了脱落，并且在这种宿主-病原体相互作用中，Ag（I）可以阻断乙烯的作用。
