FIGURE 2 Exon-intron structure and intron phases 0, 1, and 2
accounted for the proportion of all introns of AsA-GSH cycle enzyme
genes and nitrogen metabolism enzyme genes in rice and similar genes in
other species. (a) and (f), (b) and (g), (c) and (i), (d) and (h), (e)
and (j) represent the exons and intron phases 0, 1, and 2, which
accounted for the proportion of all introns in rice, Arabidopsis
thaliana , Zea mays , Hordeum vulgare , and Sorghum
bicolor , respectively. The blue rectangle represents the 5’-UTR and
3’-UTR, and the line represents introns; the unit of exon length is kb.
3.4| Effects of exogenous melatonin on the expression of
enzymes involved in the AsA-GSH cycle and nitrogen metabolism in
NaCl-stressed seedlings
As shown in (Figure
3a–d),
NaCl treatment significantly decreased AsA, GSH, and ammonium nitrogen
content and AAO, DHAR, GR, GPX, NR, GS, and GOGAT activities in
seedlings, but significantly increased nitrate-nitrogen content. The
results of exogenous melatonin at different concentrations (50–800 µmol
·L-1) opposed those of NaCl treatment. The heat maps
of OsGR3 , OsGPX1 , OsNR2 , OsGS1 , andOsGOGAT1 represented by Log2 FC values among the
different treatments were constructed (Figure 4a–b). Compared with
control treatment, the color of OsGR3 , OsGPX1 ,OsNR2 , OsGS1 , and OsGOGAT1 on the heat map was
green under NaCl stress, indicating that gene expression was
significantly downregulated; the darker the green, the greater the
degree of downregulation (Figure 4a–b). In other melatonin-pretreated
samples, the color of the genes on the heat map was reddish, even red,
indicating that the expression of the genes was upregulated; the darker
the red, the higher the degree of upregulation (Figure 4a–b).
Simultaneously, the expression levels of OsGR3 , OsGPX1 ,OsNR2 , OsGS1, and OsGOGAT1 in seedlings were
detected by RT-qPCR. The results of gene expression were found to be
similar to those on the heat map.