3.5.7. Stress Response and Disease Resistance

In 750-1, most of the unique DEGs related to stress response and disease resistance were observable in the leaves, and except for *protein SRG1-like* (*LOC107859182*) and *NBS-LRR root-knot nematode resistance protein* (*LOC107864520*), all the DEGs of the two pathways were down-regulated (Figure 7I,J). Meanwhile, in ZCFB, DEGs involved in stress response and disease resistance were detected in both the leaves and roots, and most of the genes in the leaves were down-regulated, in contrast to in the roots.

## **4. Discussion**

In this study, a large number of low-N-responsive genes were identified from low-Ntolerant (750-1) and low-N-sensitive (ZCFB) pepper genotypes after long-term N deficiency, and the number of low-N-responsive genes in ZCFB was far greater than those in 750-1 (Figure 2). The expression profiles of the genes associated with nitrate transport, assimilation, and remobilization were similar between the 750-1 and ZCFB (Figure 5). However, many unique DEGs were detected between the two pepper genotypes after long-term N deficiency, implying different molecular mechanisms of resistance to N deficiency in these two genotypes.
