03594nas a2200181 4500008004100000022001400041245014000055210006900195260001600264300001400280490000800294520297500302100001703277700001603294700001703310700002003327856006503347 2015 eng d a0929-187300aRole of salicylic acid in phosphite-induced protection against Oomycetes; a Phytophthora cinnamomi - Lupinus augustifolius model system0 aRole of salicylic acid in phosphiteinduced protection against Oo cJan-03-2015 a559 - 5690 v1413 a

Phosphite is used to control Oomycetes in a wide range of horticultural and native plant species worldwide. However, phosphite can be phytotoxic, and some pathogens have exhibited a reduction in the effectiveness of phosphite due to prolonged use. In this study, salicylic acid (SA) was investigated as an alter- native, or supplementary, treatment to be used to protect plant species. With the use of aeroponics chambers, foliar application of phosphite, SA, and phosphite/SA to Lupinus augustifolius was assessed in relation to root tip damage, in planta phosphite and SA concentration and lesion development. Both phosphite and SA were measurable at the root tip within 24 h of application, and all treatments significantly (P0.05) reduced the lesion length at 7 days. However, while phosphite and SA application increased the in planta SA concentration, phosphite caused significantly more damage to the root tip by reducing root cap layers and length than the SA, or phosphite/SA application. This study supports the notion that phosphite-induced sensitivity may be SA- dependent, as both phosphite and SA were found to control P. cinnamomi and stimulate SA accumulation. A combination of phosphite and SA may be more beneficial to plants if it can reduce phytotoxic effects and reduce the chance of pathogen sensitivity to phosphite.

1 aGroves, Emma1 aHoward, Kay1 aHardy, Giles1 aBurgess, Treena uhttp://link.springer.com/article/10.1007%2Fs10658-014-0562-y