Regulation of primary seed dormancy by MAJOR LATEX PROTEIN-LIKE PROTEIN329 in Arabidopsis is dependent on DNA-BINDING ONE ZINC FINGER6

Abstract

Seeds exhibit primary dormancy to prevent germination under unfavourable conditions. Previous studies have shown that the gibberellin signalling intermediate RGA-LIKE2 (RGL2) forms a transcription factor complex with DNA BINDING1 ZINC FINGER6 (DOF6) in regulating seed dormancy in Arabidopsis. Using RNA sequencing approach, we identified MAJOR LATEX PROTEIN-LIKE PROTEIN329 (MLP329) as a downstream target of DOF6. MLP329 is a positive regulator of primary seed dormancy, because freshly harvested unstratified mlp329 mutant seeds showed early germination, while unstratified 35S::MLP329 seeds showed poor germination. MLP329 expression level reduces in wild type (WT) seeds upon dry storage and cold stratification. MLP329 expression level is enhanced by DOF6; however, DOF6-dependent MLP329 expression is suppressed in the presence of RGL2. MLP329 expression is enhanced in abscisic acid (ABA)- and auxin (IAA)-treated seeds. Moreover, the mlp329 mutant seeds exhibited enhanced expression of GA biosynthetic gene (GA1) and suppression of ABA (ZEP) compared to the ectopic expression lines. The observed suppression of DOF6-dependent MLP329 expression by RGL2 reveals a possible negative feedback mechanism to modulate seed dormancy. MLP329 also likely enhances endogenous ABA/GA ratio to positively regulate primary seed dormancy.

Function and Characteristic Analysis of Candidate PEAR Proteins in Populus yunnanensis

“…Compared to AtHCA2, no homologs of AtDOF6 and AtTMO6 were found in P. yunnanensis. In Arabidopsis, AtDOF6 was regulator of primary seed dormancy [10]. AtTMO6 was involved in cell wound healing and tissue regeneration after squeezing and cutting treatment [13].…”

“…The following PEAR proteins have been characterized in Arabidopsis: PEAR1 (PHLOEM EARLY DOF 1, known as DOF2.4), PEAR2 (PHLOEM EARLY DOF 2, known as DOF5.1), DOF6, TMO6, OBP2, and HCA2 [9]. Before the concept of PEAR proteins was understood, these PEAR members were reported to have important functions in regulating plant growth [9][10][11][12][13][14]. Seed dormancy is an important mechanism of plant self-protection under unfavorable conditions.…”

“…DNA-BINDING ONE ZINC FINGER 6 (DOF6) acts as a negative regulator of seed germination by forming complexes with downstream proteins (such as MLP329, TCP14, etc.) to regulate primary seed dormancy [10,11]. The DELLA protein RGA-LIKE2 (RGL2) forms a complex with DOF6 that can active GATA12 (a gene that encodes GATA-type zinc finger transcription factor) to enforce primary seed dormancy [12].…”

Stimulating effect of biogenic nanoparticles on the germination of basil (Ocimum basilicum L.) seeds

“…However, due to the seed coat penetration properties of NPs, ZnO-NP positively affected germination at low concentration (25 mg/L), while it caused toxic effects at higher concentrations. The fact that GI parallels the increase in ZnO-NP (25 mg/L) concentration can be explained by the need for Zn, which is the most critical micronutrient, for the activation of enzymes involved in protein and carbohydrate synthesis, nucleic acid and lipid regulation, and the breaking of primary seed dormancy [19]. Higher concentrations negatively affected the GI due to damage to plant cells, even causing toxic effects.…”

Host organelles and transporters in underground plant-pathogen interactions

“…The more distantly MLP6-related gene At3g26460 in group II is coexpressed with NPF5.12 (Genevestigator) and, together with AtMLP328, is transcriptionally downregulated by P. brassicae infection(Irani et al 2018). MLP329 is a positive regulator of seed dormancy(Chong et al 2022) and iron homeostasis(Xing et al 2015;Martín-Barranco et al 2020), and both AtMLP328 and AtMLP329 are involved in vegetative growth promotion(Guo et al 2011). As more functional information is generated regarding MLPs, more examples of individual MLP multifunctionality will emerge.…”