In many woody plants, rooting ability is expressed at the base of the stem, which retains juvenile characteristics throughout the plant life, and is sharply or gradually lost upon transition to the mature phase [ 2].
In woody plants, the juvenile traits, including rooting capability, are expressed at the base of the stem throughout the life of the plant and are sharply or gradually replaced by maturity traits, including rooting inability, toward the upper part of the main stem and branches [ 5].
The SLL1 gene was expressed at the lateral root tip, whereas SLL1 expression was not detected in the elongation zone of the crown roots.
Notably, we found an abundant transcript encoding Rac-like GTP-binding protein, which was preferentially expressed at the tip of root hairs and believed to be involved in cell polarity control during the actin-dependent tip growth of root hairs [ 37, 38].
Interestingly, the tomato NBS-LRR-encoding R gene, I-2, is expressed at the site of lateral root formation indicating that it might have a role in lateral root initiation in addition to disease resistance [ 38].
The tomato I-2 gene (CNL type) is expressed at the site of lateral root formation suggesting that it may have functions in addition to pathogen recognition [ 38].
According to the RPKM values of the genes encoding enzymes involved in alkaloid biosynthesis in leaves, roots and flowers shown in Table 5, most of the enzymes were expressed at the lowest level in roots, in particular polyphenol oxidase (PPO), which has a role in plant resistance to stress and pathogens.
SiLEA14 was expressed at the highest level in roots, followed by stems and leaves, and at the lowest level in inflorescences.
Moreover, soybean Hsf genes were expressed at the highest level in roots and at the lowest level in seeds after 21 days of development.
