Increased senescence-associated gene expression and lipid peroxidation induced by iron deficiency in rice roots

Abstract

Iron deficiency is among the most common nutritional disorders in plants. Low iron supply causes decreased root growth and even plant death. However, there are no reports about the specific pathways that lead Fe-deficient roots to senescence and death. To investigate the molecular mechanisms that regulate rice roots response to Fe-deficiency, rice seedlings were grown for 3, 6 and 9 days in the presence or absence of Fe. Sequences of 28 induced genes in rice roots under Fe-deficiency were identified by representational difference analysis (RDA). About 40% of these sequences have been previously reported as senescence-related. Differential expression of selected genes was confirmed by semi-quantitative RT-PCR analysis. Classical senescence-related sequences, such as MYB and WRKY transcription factors, cysteine protease, ubiquitin-conjugating enzyme, lipid transfer protein, fatty acid hydroxylase, beta-glucosidase and cytochrome P450 oxydoreductase were identified. Fe-deficiency also resulted in decreased dry weight, increased lipid peroxidation (detected by TBA and histochemical methods) as well as evident membrane damage in Fe-deficient roots. Taken together, the results indicate that Fe-deficiency in roots is linked to typical senescence pathways, associated with lipid peroxidation.

Natural variation in iron use efficiency and mineral remobilization in cucumber (Cucumis sativus)

“…Nitrogen deficiency stress is known to result in premature senescence (Crafts-Brandner et al 1998). Fe deficiency may also accelerate senescence (Sperotto et al 2008(Sperotto et al , 2007. In our experiments, K was remobilized earlier time points from MW, and P remobilization occurred at earlier time points in Ashley when Fe was withheld.…”

Systems and Trans-System Level Analysis Identifies Conserved Iron Deficiency Responses in the Plant Lineage

“…Among them, we identified three Myb-like transcription factors (MYB4, MYB16, and Cre12.g514400). Myb-like transcription factors have been previously associated with iron deficiency in plants, where they might function as regulators of iron deficiency responses (Chen et al, 2006;Ogo et al, 2006;Shen et al, 2008) or they are involved in senescence (Sperotto et al, 2008). Additionally, three genes coding for GCN5-related N-acetyltransferases (NAT19, NAT30, and NAT4) were strongly upregulated (Table 1).…”

Identification of up-regulated genes in flag leaves during rice grain filling and characterization of OsNAC5, a new ABA-dependent transcription factor

“…Several genes previously associated with senescence processes in rice have been identiWed in our experiment (Supplementary Table 1), including the genes encoding: Ubiquitin-conjugating enzyme, GDSL-motif lipase/hydrolase family protein, Lipid transfer protein and J023008A06 Senescence-associated protein Sperotto et al 2008). The higher expression of such genes in Xag leaves during grain Wlling (R5) suggest that a senescence process is already occurring, even without leaf chlorosis, the most obvious signal of leaf senescence.…”