Effect of Temperature Treatments on the Penetration and Disease Development in the Leaf Epidermis by the Rice Blast Fungus, Pyricularia oryzae Cavara II. Difference in Percent Penetration, Hyphal Growth and Lesion Formation by Pre­ and Postdisposing Temperatures

기온변동이 벼 도열병균의 엽신에의 침입과 발병에 미치는 영향 II. 접종전 및 접종시의 온도처리에 의한 침입$\cdot$균사신전$\cdot$병반형성 차이

Three rice cultivars, Aichi-asahi, Toyotama and Yamabiko, possessing a resistance gene $Pi-\alpha$ were evaluated for penetration, hyphal growth in the leaf epidermis and lesion formation using 6 isolates of Pyricularia oryzae by treating pre- and post disposing temperatures of $23/15^{\circ}C\;and\;29/21^{\circ}C$ (day/night) regimes, respectively. Percent penetration of the fungus was higher on the seedlings disposed at $29/21^{\circ}C$ regime and more lesions were formed at 7 days after inoculation than at $23/15^{\circ}C$ regime. Degree of hyphal growth and number of host cells with hyphal growth were remarkably increased from 72 to 96 hr after inoculation at $29/21^{\circ}C$ regime. However, lesion formation on the seedlings disposed at $23/15^{\circ}C$ regime was delayed, possibly as a result of the suppressed hyphal growth until 96 hr after inoculation.

도열병 저항성유전자 $Pi-\alpha$를 가지고 있는 Aichi-asahi, Toyotama, Yamabiko를 공시하여 접종전$\cdot$접종후 $23/15^{\circ}C\;,\;29/21^{\circ}C$에 각각 3일간 처리하였다. 도열병균 6개 균주를 접종한 후, 도열병균의 침입$\cdot$균사신전$\cdot$병반수를 조사한 결과, $29/21^{\circ}C$에 처리한 유균에서 침입율이 높고 형성 병반수도 많았다. 균사신전도와 피침입세포수는 $29/21^{\circ}C$ 경우 접종후 72시간에서 96시간 사이에 현저히 증가하였다. 그러나 $23/15^{\circ}C$에 처리한 유균에서 침입$\cdot$균사신전이 억제되어 병반형성이 지연되었다