Manipulation of Growth and Architectural Characteristics in Trees for Increased Woody Biomass Production

Abstract

Growth and architectural traits in trees are economically and environmentally important and thus of considerable importance to the improvement of forest and fruit trees. These traits are complex and result from the operation of a number of molecular mechanisms. This review will focus on the regulation of crown architecture, secondary woody growth and adventitious rooting. These traits and processes have significant impact on deployment, management, and productivity of tree crops. The majority of the described work comes from experiments in model plants, poplar, apple, peach, and plum because these species allow functional analysis of the involved genes and have significant genomics resources. However, these studies convincingly show conserved mechanisms for elaboration of specific growth and architectural traits. The conservation of these mechanisms suggest that they can be used as a blueprint for the improvement of these traits and processes in phylogenetically diverse tree crops. We will specifically consider the involvement of flowering time, transcription factors and hormone-associated genes. The review will also discuss the impact of recent technological advances as well as the challenges to the dissection of these traits in trees.

Sucrose synthase determines carbon allocation in developing wood and alters carbon flow at the whole tree level in aspen

“…Primary metabolic reactions are especially important in this process because they are responsible for sucrose catabolism, energy production, and the synthesis of the precursors for cell wall polymers. Studies on biomass accumulation in trees commonly focus on hormonal factors and C allocation to cell wall polymers (Dubouzet et al ., 2013; Busov, 2018), while primary metabolism has received less attention (Mahboubi & Niittylä, 2018). The C availability for biomass production by sink tissues depends on the photosynthetic and sucrose export capacity of source leaves (Yu et al ., 2015); in recognition of this, efforts have been made to increase wood biomass by improving tree photosynthesis (Dubouzet et al ., 2013; Busov, 2018).…”

“…Studies on biomass accumulation in trees commonly focus on hormonal factors and C allocation to cell wall polymers (Dubouzet et al ., 2013; Busov, 2018), while primary metabolism has received less attention (Mahboubi & Niittylä, 2018). The C availability for biomass production by sink tissues depends on the photosynthetic and sucrose export capacity of source leaves (Yu et al ., 2015); in recognition of this, efforts have been made to increase wood biomass by improving tree photosynthesis (Dubouzet et al ., 2013; Busov, 2018). However, C acquisition, allocation, and metabolism in the different tissues of a tree depend on the relationship between sink and source tissues, which should therefore be considered jointly (Sonnewald & Fernie, 2018).…”

Knockdown of miR393 Promotes the Growth and Biomass Production in Poplar

“…At present, there is a large demand for wood, and cultivating fast-growing trees like poplar is a promising way to solve this problem. To further improve poplar growth and biomass production, substantial efforts have been made to identify the functions of genes and small RNAs that regulate poplar growth (Lucas et al, 2013;Sundell et al, 2017;Busov, 2018). MicroRNAs (miRNAs) can negatively regulate the transcription and post-transcription of their specific target genes by binding their near-perfect complementary sites through its 20-24 nucleotides, which can lead to the target mRNA degradation and/or translational repression (Meyers et al, 2008;Voinnet, 2009).…”

Genetic Modification of KNAT7 Transcription Factor Expression Enhances Saccharification and Reduces Recalcitrance of Woody Biomass in Poplars

“…Lignocellulosic biomass from secondary cell walls (SCW) is one of the most promising bioenergy feedstocks for producing second-generation bioethanol ( Demura and Ye, 2010 ; Nookaraju et al, 2013 ; Zhong et al, 2019 ). The unraveling of the poplar genome sequence by Tuskan et al (2006) has opened up many new avenues into the production of transgenic poplars with altered expression of cell wall genes for enhanced saccharification and biomass growth assisting in an efficient bioconversion of cell wall biomass to bioethanol ( Sahoo and Maiti, 2014 ; Busov, 2018 ; Cho et al, 2019 ; Bryant et al, 2020 ). A battery of transcription factors (TFs) regulates SCW formation ( Zhong and Ye, 2014 ).…”