Effect of Abiotic and Biotic Elicitors on Growth and Alkaloid Accumulation of Lycoris chinensis Seedlings

Three-month-old seedlings of Lycoris chinensis were treated with biotic and abiotic elicitors: yeast elicitor (YE), methyl jasmonate (MJ), salicylic acid (SA), and sodium nitroprusside as NO donator (NO). We have shown that the addition of MJ and NO promotes the accumulation of galanthamine in these seedlings. The effect of these elicitors on the growth of the seedlings, as well as on the amount of the alkaloids accumulated in the seedlings was studied. The results showed that, in general, high doses of MJ and SA had a negative effect on the growth of the seedlings, while appropriate doses of NO and YE had a positive effect on the growth of the seedlings. It was remarkable that the addition of MJ, NO, and YE can promote galanthamine accumulation in seedlings. The accumulation was higher in treatments at higher concentrations of NO (100 μM), where the release of galanthamine was 1.72-fold higher than that of the control at the 10th day of culture. The highest values of lycorine were obtained in seedlings treated with YE at a concentration of 0.01 g/l and by the 10th day of culture; the level was 1.38 times of the control.

Induction of resistance to fire blight in apple (Erwinia amylovora)

Apple genotypes show different levels of resistance to fire blight caused by the bacterium E. amylovora. This resistance is considered to be polygenic, thus relying on a number of defense mechanisms. On the assumption that in susceptible genotypes these defenses may be present but not activated during the infection process, we attempted their induction by various abiotic and biotic elicitors. Two kinds of experiments were performed in the greenhouse and in the orchard: i) evaluation after controlled inoculation of the level of protection conferred to the plant by each elicitor and ii) investigation of various defense responses potentially involved in the protection. Results showed that some elicitors provided a level of overall protection of about 50% in the orchard while higher levels may be obtained on seedlings in the greenhouse. The comparison of some defense responses in protected and unprotected treated plants showed that i) elicitation of defense is not necessarily associated with control of fire blight and that ii) some responses at least may be associated with the observed protection.