Shoot and root branch growth angle control—the wonderfulness of lateralness

Abstract

The overall shape of plants, the space they occupy above and below ground, is determined principally by the number, length, and angle of their lateral branches. The function of these shoot and root branches is to hold leaves and other organs to the sun, and below ground, to provide anchorage and facilitate the uptake of water and nutrients. While in some respects lateral roots and shoots can be considered mere iterations of the primary root-shoot axis, in others there are fundamental differences in their biology, perhaps most conspicuously in the regulation their angle of growth. Here we discuss recent advances in the understanding of the control of branch growth angle, one of the most important but least understood components of the wonderful diversity of plant form observed throughout nature.

The Arabidopsis LAZY1 Family Plays a Key Role in Gravity Signaling within Statocytes and in Branch Angle Control of Roots and Shoots

“…The growth angle of organs is maintained at specific angles with respect to gravity (gravitropic set-point angle [GSA]) according to developmental control and environmental factors, a concept that provides a unifying explanation for ortho-, plagio-, and diagravitropism (Digby and Firn, 1995). Recent investigations of growth angle control in the lateral roots and shoots of Arabidopsis suggested that an antagonistic interaction between two balancing auxin-dependent growth components, gravitropism and antigravitropic offset, underlies the mechanism of GSA control (Roychoudhry et al, 2013;Roychoudhry and Kepinski, 2015). Based on the concept of GSA control, the growth angle phenotype of lzy1 lzy2 lzy3 lateral roots and shoots might be the result of an imbalance between gravitropism and antigravitropic offset.…”

Integrative RNA- and miRNA-Profile Analysis Reveals a Likely Role of BR and Auxin Signaling in Branch Angle Regulation of B. napus

“…Plant architecture and above ground shape are mainly determined by the number, length, and angle of branches [8]. Appropriate shoot branch angles are required to produce leaves and other organs orientated for the most efficient light interception [41].…”

“…Tiller or branch angle has been well investigated among crops including rice and maize, owing to its’ agronomic importance [6,7]. Moreover, the growth angle of branches and other lateral organs are also emerging as important topics for plant developmental research [8]. …”

“…Changes in the expression levels of genes involved in auxin synthesis or signaling transduction have been shown to result in differences in the tiller angle and gravitropic response [8]. In addition to auxin, brassinosteroids (BRs) have been reported to be involved in leaf angle determination [17].…”

A Novel Tiller Angle Gene, TAC3, together with TAC1 and D2 Largely Determine the Natural Variation of Tiller Angle in Rice Cultivars

“…In the past decade, ~11 genes were reported to control tiller angle in rice [32]. However, in the present study, only TAC1 was detected in the local LD region via GWAS in both Hainan and Wuhan (Table 2).…”