Women in Plant Cell Biology: 2022

Editors

LUCIANA RENNA

University of Florence

Emily Palm

University of Milano-Bicocca

Impact

Specific antibodies against cardosin A and α-TIP were used coupled to a 15-nm (yellow circles) and 10-nm gold-conjugated secondary antibody (red circles), respectively. (A) Schematic representation of the procedure. (B) Cardosin A labeling was detected inside the protein storage vacuoles (a, b yellow circles), while anti-α-TIP conjugated with 10 nm gold particles decorates the periphery of the same structures (red circles). Anti-α-TIP conjugated alone was used as a control (c-e). Scale bars: (B) a, 300 nm; b, 200 nm; c, d, 500 nm; e, 200 nm.

Original Research

07 July 2023

The journey of cardosin A in young Arabidopsis seedlings leads to evidence of a Golgi-independent pathway to the protein storage vacuole

Cláudia Pereira

, 2 more and

Susana Pereira

2,310 views

0 citations

(A), SEC14 protein-mediated lipid transfer and heterotypic exchange of lipids between two membranes. (B), Lipid presentation model, interaction of SEC14 protein with PI kinase and phosphorylation of lipid during transfer (de Campos and Schaaf, 2017). (C), Regulation of membrane binding by phosphorylation of SEC14 domain by a protein kinase. (D), Increase in the number of potential protein-protein interactions of multi-domain versus single-domain SEC14L-PITPs. (E), Alphafold model of the multi-domain SEC14 protein PATL2 (At1g22530). The arrows point to a) intrinsically disordered N-terminal region; b) CTN domain; c) SEC14 domain with lipid-binding site, gate and anchor helices; d) GOLD domain. Alphafold was used, as described (Jumper et al. 2021; Varadi et al. 2021). (F), Symbols used in (A–D).

Review

15 May 2023

Role of SEC14-like phosphatidylinositol transfer proteins in membrane identity and dynamics

Karolin Montag

, 1 more and

Petra Bauer

2,036 views

1 citations

(A) Seven-day-old seedlings of the wild types (Col-0 and Ws) and the mutants iaa28-1, slr1-1, and cul1-6 were transferred to control (gray bar) or Sortin2 (black bar) treatment conditions. The density of lateral root primordia (LRPs) was evaluated after 72 hours in three independent experiments (n ≥ 26 seedlings). (B, C) The transcript levels of GATA23 (B) and MAKR4 (C) were evaluated in 7-day-old seedlings of Col-0, iaa28-1, and slr1-1 after 24 hours of Sortin2 treatment. RNA was isolated from a pool of seedlings (n ≥ 60) from three independent experiments, and transcript levels of lateral root related genes and reference genes were evaluated by RT-qPCR. Shown are transcript levels of biological triplicates relative to the level in Col-0 seedlings in control conditions (dashed line). The results were analyzed using Student’s t-tests and Wilcoxon tests (**p < 0.01; ***p < 0.001; ns: not significant). (D) The effect of auxinole (20 μM) on Sortin2-induced LRP formation. Seven-day-old pCYCB1;1::GUS seedlings were treated with Sortin2, auxinole, and Sortin2 plus auxinole, and the number of LRPs was scored after 5 days. Results from three experimental replicates are shown (n = 25 [Control], 35 [Sortin2], 15 [NAA], 35 [auxinole], 12 [NAA+auxinole], 32 [Sortin2+auxinole] seedlings). Results were analyzed using Student’s t-tests; brackets denote statistical differences between conditions (**p < 0.01; *** p < 0.001; ns, not significant).

Original Research

16 January 2023

Endocytic trafficking induces lateral root founder cell specification in Arabidopsis thaliana in a process distinct from the auxin-induced pathway

Stefanía Morales-Herrera

, 2 more and

Lorena Norambuena

2,111 views

1 citations

Original Research

13 December 2022

Alkaline stress reduces root waving by regulating PIN7 vacuolar transport

Yu Liu

, 8 more and

Ruixi Li

(A) The root phenotype of 6-d-old wild-type seedlings and pin7 mutants under control (pH 5.8) or alkaline (pH 8.0) conditions. Scale bar, 5 mm; (B) Quantification of the primary root length as demonstrated in (A) Values are mean ± SD (n > 40 seedlings). (C) Auxin distribution pattern as revealed by the DR5rev::GFP reporter in wildtype seedlings and pin7 mutants under control (pH 5.8) or alkaline (pH 8.0) conditions. (D, E, F) Statistical analysis of the spatial wave frequency (wave/mm) (D), temporal wave frequency (waves/d) (E), and root axis angle (F) in wild-type seedlings and pin7 mutants as shown in (A) (n > 40 seedlings). (G) Relative auxin level as revealed by the DR5rev::GFP reporter in wild-type and pin7 mutants as shown in (C) (n > 15). Statistically significant differences were determined by using student’s t-test (* P < 0.05; *** P < 0.001).

Root development and plasticity are assessed via diverse endogenous and environmental cues, including phytohormones, nutrition, and stress. In this study, we observed that roots in model plant Arabidopsis thaliana exhibited waving and oscillating phenotypes under normal conditions but lost this pattern when subjected to alkaline stress. We later showed that alkaline treatment disturbed the auxin gradient in roots and increased auxin signal in columella cells. We further demonstrated that the auxin efflux transporter PIN-FORMED 7 (PIN7) but not PIN3 was translocated to vacuole lumen under alkaline stress. This process is essential for root response to alkaline stress because the pin7 knockout mutants retained the root waving phenotype. Moreover, we provided evidence that the PIN7 vacuolar transport might not depend on the ARF-GEFs but required the proper function of an ESCRT subunit known as FYVE domain protein required for endosomal sorting 1 (FREE1). Induced silencing of FREE1 disrupted the vacuolar transport of PIN7 and reduced sensitivity to alkaline stress, further highlighting the importance of this cellular process. In conclusion, our work reveals a new role of PIN7 in regulating root morphology under alkaline stress.

2,375 views

4 citations

(A) Images of the root hairs of five-day old wild type, ccdc22-1 and CCDC22:CCDC22-RFP (ccdc22-1) seedlings grown on 1X MS media, Scale bars are equal to 100 mm. (B) Relative root hair lengths of the indicated genotypes as compared to wild type (WT). Represented is the combined data from three independent experiments in which 15 root hairs per seedling and 10 seedlings per genotype were measured. (C) Expression of a C-terminal RFP fusion to CCDC22 in the ccdc22-1 background resulted in complementation of the ccdc22-1 short root phenotype. Scalebars are equal to 1mm. (D) Relative root growth (%) of the indicated genotypes. Letters above the bars represent statistically significant groupings at the level of p <0.001 as determined by analysis of variance (ANOVA) and Tukey’s honestly significance difference tests.

Original Research

22 December 2022

CCDC22 and CCDC93, two potential retriever-interacting proteins, are required for root and root hair growth in Arabidopsis

Connor D. Lewis

, 1 more and

Mary L. Tierney

2,142 views

1 citations

Original Research

11 November 2022

Carbon monoxide promotes stomatal initiation by regulating the expression of two EPF genes in Arabidopsis cotyledons

Xianjie Weng

, 7 more and

Xiaolan Chen

The gaseous molecule carbon monoxide (CO) can freely pass through the cell membrane and participate in signal transduction in the cell to regulate physiological activities in plants. Here, we report that CO has a positive regulatory role in stomatal development. Exogenous CO donor CORM-2 [Tricarbonyldichlororuthenium (II) dimer] treatment resulted in an increase of stomatal index (SI) on the abaxial epidermis of cotyledons in wild-type, which can be reversed by the addition of the CO biosynthesis inhibitor ZnPPIX [Protoporphyrin IX zinc (II)]. Consistent with this result, mutation of the CO biosynthesis gene HY1 resulted in a decrease of SI in hy1-100 plants, while overexpression of HY1 led to an increase of SI. Further investigation revealed that CO acts upstream of SPCH and YDA in the stomatal development pathway, since the loss of function mutants spch-1 and yda-2 were insensitive to CORM-2. The expression of EPF2 was inhibited by CORM-2 treatment in wild type and is lower in hy1 than in wild-type plants. In contrast, the expression of STOMAGEN was promoted by CORM-2 treatment and is higher in HY1-overexpression lines. Loss of function mutants of both epf2 and stomagen are insensitive to CORM-2 treatment. These results indicated that CO positively regulates stomatal initiation and distribution by modulating the expression of EPF2 and STOMAGEN.