The Arabidopsis TETRATRICOPEPTIDE THIOREDOXIN-LIKE 1 Gene Is Involved in Anisotropic Root Growth during Osmotic Stress Adaptation

Abstract

Mutations in the Arabidopsis TETRATRICOPEPTIDE THIOREDOXIN-LIKE 1 (TTL1) gene cause reduced tolerance to osmotic stress evidenced by an arrest in root growth and root swelling, which makes it an interesting model to explore how root growth is controlled under stress conditions. We found that osmotic stress reduced the growth rate of the primary root by inhibiting the cell elongation in the elongation zone followed by a reduction in the number of cortical cells in the proximal meristem. We then studied the stiffness of epidermal cell walls in the root elongation zone of ttl1 mutants under osmotic stress using atomic force microscopy. In plants grown in control conditions, the mean apparent elastic modulus was 448% higher for live Col-0 cell walls than for ttl1 (88.1 ± 2.8 vs. 16.08 ± 6.9 kPa). Seven days of osmotic stress caused an increase in the stiffness in the cell wall of the cells from the elongation zone of 87% and 84% for Col-0 and ttl1, respectively. These findings suggest that TTL1 may play a role controlling cell expansion orientation during root growth, necessary for osmotic stress adaptation.

Developmental Signals in the 21st Century; New Tools and Advances in Plant Signaling

“…A fruitful aspect discussed in the work involves the issue of the impact of the FLA4-FEI pathway on agronomic traits, such as improving plant resistance to several abiotic and biotic stresses in multiple crops. In line with this, as reported in this issue by Cuadrado-Pedetti et al [3], drought conditions cause stress to the plant, and the plant will try to adapt to these conditions. A large number of genes have been identified that allow plants to face these conditions; several of these genes have a function in root development.…”

“…Developmental processes can influence CWs, but also CWs can affect plant development. In this issue, two reviews [1,2] and a research paper [3] studied these aspects. In the work of Cruz-Valderrama et al, 2021, authors reviewed what is known about the importance of the CW during flower development [2].…”

“…Based on mutant analyses, TTL1 is involved in determining the stiffness of the cell wall of the cells from the root elongation zone. The authors concluded that TTL1 is involved in anisotropic root growth during osmotic stress adaptation [3].…”

Genome-Wide Comprehensive Analysis of the GASA Gene Family in Populus

“…AtGASA1, the homolog of PeuGASA15, has been reported to weakly interact with VIT by phage display technology [60]. VIT, also named TETRATRICOPEPTIDE-REPEAT THIOREDOXIN-LIKE 1 (TTL3), plays an important role in brassinosteroid and auxin signaling, and is required for osmotic stress tolerance [60][61][62][63][64][65]. Consistent with Arabidopsis, IAA induced PeuGASA15 expression and mannitol significantly inhibited PeuGASA15 expression in the leaves of pGASA15: GUS transgenic leaves (Figure 11).…”

Analysis of Thioredoxins and Glutaredoxins in Soybean: Evidence of Translational Regulation under Water Restriction

“…Moreover, from the 12 DEG GmTrx , GmTrx92 was exclusively regulated, specifically down-regulated, at the translational level ( Figure 4 b; Table 1 ). This protein had high homology with Arabidopsis TTL1 ( Supplementary Figure S2 ) for which a role in the root adaptation during osmotic stress is suggested [ 76 ]. It is worth noting that four out of five soybean nucleoredoxins were DEGs in nodulated and water-restricted plants; specifically, they were up-regulated at the TOTAL+PAR level in the N+WR vs. N+WW contrast ( Figure 4 b; Table 1 ).…”