Abstract
Fusarium verticillioides is one of the most relevant fungal species in maize responsible for ear, stalk and seedling rot, as well as the fumonisin contamination of kernels. Plant lipoxygenases (LOX) synthesize oxylipins that play a crucial role in the regulation of defense mechanisms against pathogens and influence the outcome of pathogenesis. To better uncover the role of these signaling molecules in maize resistance against F. verticillioides, the functional characterization of the 9-LOX gene, ZmLOX4, was carried out in this study by employing mutants carrying Mu insertions in this gene (named as UFMulox4). In this regard, the genotyping of five UFMulox4 identified the mutant UFMu10924 as the only one having an insertion in the coding region of the gene. The impact of ZmLOX4 mutagenesis on kernel defense against F. verticillioides and fumonisin accumulation were investigated, resulting in an increased fungal susceptibility compared to the inbred lines W22 and Tzi18. Moreover, the expression of most of the genes involved in the LOX, jasmonic acid (JA) and green leaf volatiles (GLV) pathways, as well as LOX enzymatic activity, decreased or were unaffected by fungal inoculation in the mutant UFMu10924. These results confirm the strategic role of ZmLOX4 in controlling defense against F. verticillioides and its influence on the expression of several LOX, JA and GLV genes.
Highlights
Maize is the most widely grown cereal crop, with a world production of more than one billion tons from about 200 million ha [1]
The expression of most of the genes involved in the LOX, jasmonic acid (JA) and green leaf volatiles (GLV) pathways, as well as LOX enzymatic activity, decreased or were unaffected by fungal inoculation in the mutant UFMu10924
Mu transposon insertions in the ZmLOX4 gene were confirmed by PCR amplification, followed by DNA sequencing (Figure 1, Figure S1)
Summary
Maize is the most widely grown cereal crop, with a world production of more than one billion tons from about 200 million ha [1]. Five novel maize mutants carrying transposon Mu insertions in distinct regions of the ZmLOX4 gene (hereafter named as UFMulox4), together with inbred lines W22 and Tzi, were tested for resistance to Fusarium seedling rot (FSR) caused by F. verticillioides, using an inoculation assay in germinating kernels. This method allowed a better evaluation of infection progress at both kernel and seedling stages [38,39,40]. F. verticillioides and supplying new information about how the altered expression of this gene could, in turn, reduce the transcriptional levels of several LOX and GLV genes
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
