ABA alleviates nitrate-mediated Fe deficiency response
Previous studies have shown that
nitrogen deficiency resulted in the accumulation of ABA (Krauss et al,
1978; Teplova et al, 1998) and our RNA-seq analysis also demonstrated
that nitrate treatment affected the expression of genes related to ABA
metabolism and signaling (Fig. S6). Considering ABA plays a role in
alleviating Fe deficiency response (Lei et al. 2014), it seems likely
that it is also involved in nitrate-regulated iron deficiency responses.
To assess this possibility, endogenous ABA content was measured in
seedlings of ‘Pinyiensis ’ under different nitrate treatments. ABA
content increased with LN treatment in roots (Fig. 7b), while there was
no apparent difference in ABA content in leaves (Fig. 7a). Meanwhile,
exogenous ABA application partially rescued the chlorosis phenotype in
response to HN treatment (Fig. 7c, d). These results indicated that LN
promoted ABA accumulation in roots quickly, and that LN alleviated iron
deficiency partially through promoting ABA accumulation in roots.