Ramie (pronounced: /ˈreɪmi/, RAY-mee; from Malay rami) is a flowering plant in the nettle family Urticaceae, native to eastern Asia. It is a herbaceous perennial growing to 1.0–2.5 m (3 ft 3 in–8 ft 2 in) tall;[1] the leaves are heart-shaped, 7–15 cm (2.8–5.9 in) long and 6–12 cm (2.4–4.7 in) broad, and white on the underside with dense, small hairs—this gives it a silvery appearance; unlike stinging nettles, the hairs do not sting. The true ramie or China grass is also called Chinese plant or white ramie.
A second type, known as green ramie or rhea, is believed to have originated in the Malay Peninsula[citation needed]. It has smaller leaves which are green on the underside, and it appears to be better suited to tropical conditions. The word "ramie" is derived from the Malay word rami.
Ramie is one of the strongest natural fibers. It exhibits even greater strength when wet. Ramie fiber is known especially for its ability to hold shape, reduce wrinkling, and introduce a silky lustre to the fabric appearance. It is not as durable as other fibers, so is usually used as a blend with other fibers such as cotton or wool. It is similar to linen in absorbency, density, and microscopic appearance. It does not dye as well as cotton. Because of its high molecular crystallinity, ramie is stiff and brittle and will break if folded repeatedly in the same place; it lacks resiliency and is low in elasticity and elongation potential
Phloem protein 2 (PP2) is one of the most abundant and enigmatic proteins in sieve elements and companion cells, which play important roles in the maintenance of morphology, photoassimilate transportation and wound protection in higher plants, but to date, no PP2 (BnPP2) genes had been identified in ramie. Here, a total of 15 full-length BnPP2 genes were identified. These BnPP2 genes exhibited different responses to abiotic stresses. Interestingly, the BnPP2 genes are more sensitive to insect pests than to other stresses. A study of the BnPP2-15 promoter revealed that pBnPP2-15 could drive specific GUS expression in the petiole, root and stamen and could also be induced by mechanical wounding and aphid infection in transgenic Arabidopsis lines. The subcellular localization of six BnPP2 proteins showed that GFP-BnPP2-1, GFP-BnPP2-6, GFP-BnPP2-7, GFP-BnPP2-9, GFP-BnPP2-11 and GFP-BnPP2-12 were predominantly located in the cytoplasm. These results provide useful information elucidating the functions of BnPP2 genes in ramie.