Birches

Abstract

The birches are common trees and shrubs of the northern hemisphere. Economically, the most important species is the silver birch ( Betula pendula ), and its breeding started already in 1940s. To speed up breeding, new biotechnological approaches have been introduced, including marker‐assisted breeding, micropropagation, and gene transfer. Possibilities to improve wood quality and stress tolerance are now being studied by using these technologies. Several genes regulating flower development in birch have been isolated, and utilized in development of nonflowering and early‐flowering birches. The only biotechnological applications related to herbivore and fungal resistance so far appear to be the transformation of spider insecticidal peptide gene into Betula platyphylla , and of chitinase IV gene from sugar beet into silver birch. Attempts to modify lignin amount and composition have been made with two genes, but neither of these lead to expected alterations in lignin composition. Birch is quite tolerant to some toxic compounds found in contaminated soil, but so far no transgenic applications for phytoremediation have been reported. The recently established large expressed sequence tag (EST) library and birch oligonucleotide microarray chips will undoubtedly enable further genomic studies on birch and enhance its potential as a deciduous woody model plant.

Abiotic stresses induced physiological, biochemical, and molecular changes in <i>Betula platyphylla</i>: a review

“…It is a deciduous and pioneer woody plant (Guo et al 2017a) that has heterophyllous leaves (Hoshika et al 2013b) and is a cold-tolerant species (Chen et al 2019). This species belongs to the Betulaceae family (IPNI 1911;WCSP 2013) and shares the same genus as B. pendula Roth (Lemmetyinen et al 2008;Gang et al 2019aGang et al , 2019bWang et al 2019a) , B. luminifera H.J.P.…”

“…However, comparing with crops, studies of abiotic stress tolerance of forest trees, and research on resistance breeding are still in their infancy (Niinemets 2010). This is mainly because woody plant breeding is very slow due to its large size, long generation cycle, as well as need a long time to test tree economic value (Lemmetyinen et al 2008). Abiotic stresses are increasing, and only a few tree species can grow normally in such conditions.…”

Clonal variation in Scots pine (Pinus sylvestris) and in transgenic silver birch (Betula pendula)

“…Both the particle bombardment (Valjakka et al 2000, Tiimonen et al 2005 and the Agrobacterium based (Aronen et al 2002, Pappinen et al 2002, Lemmetyinen et al 2004, Lännenpää et al 2005, Zeng et al 2010, Zhang et al 2012 gene transfer methods have been developed for silver birch. The transformed properties include modification of host-pathogen interaction (Pappinen et al 2002, insect resistance (Zeng et al 2010), flowering (Lemmetyinen et al 2004, Lännenpää et al 2005, lignin biosynthesis (Tiimonen et al 2005, Sutela et al 2009, Seppänen et al 2007), nitrogen metabolism (Valjakka et al 2000) and morphology, xylem structure and chemistry (Piispanen et al 2003). Also, transient transformation system of birch is developed for the functional characterization of genes and protein production (Zhang et al 2012).…”