Project description:Transcriptomic profile of Arabis alpina apex enriched material. We compared apices from plants grown for 2 weeks in long days (20°C) (juvenile) with apices from plants grown for 8 weeks in long days (20°C) (adult) and apices from plants grown for 2 weeks and then shifted in vernalization for 4 weeks with apices from plants grown for 8 weeks and than shifted to vernalization for 4 weeks.
Project description:Transcriptomic profile of Arabis alpina apex enriched material. We compared apices from plants grown for 2 weeks in long days (20M-BM-0C) (juvenile) with apices from plants grown for 8 weeks in long days (20M-BM-0C) (adult) and apices from plants grown for 2 weeks and then shifted in vernalization for 4 weeks with apices from plants grown for 8 weeks and than shifted to vernalization for 4 weeks. 2x2 factorial design. 2 starting ages (2 weeks and 8 weeks) and 2 developmental conditions (before and after vernalization). 4 biological replicates for each condition (16 arrays). Reference: pool of the 16 arrays.
Project description:Arabis alpina, similar to woody perennials, has a complex architecture with a zone of axillary vegetative branches and a zone of dormant buds that serve as perennating organs. We show that floral development during vernalization is the key for shaping the dormant bud zone by facilitating a synchronized and rapid growth after vernalization and thereby causing an increase in auxin transport, response and endogenous indole-3-acetic acid (IAA) levels in the stem. Floral development during vernalization is associated with the development of axillary buds in subapical nodes. Our transcriptome analysis indicated that these buds are not dormant during vernalization but only reach sustained growth after the return to warm temperatures. Floral and subapical vegetative branches grow after vernalization and inhibit the development of the buds below. Dormancy in these buds is regulated across the A. alpina life cycle by low temperatures and by apical dominance in a BRANCHED 1 dependent mechanism.
Project description:Perennial plants maintain their life span through several growth seasons. Arabis alpina serves as model Brassicaceae species to study perennial traits. A. alpina lateral stems have a proximal vegetative zone with a dormant bud zone, and a distal senescing seed-producing inflorescence zone. We addressed the questions of how this zonation is distinguished at the anatomical level, whether it is related to nutrient storage, and which signals affect the zonation. We found that the vegetative zone ehxibits secondary growth, which we termed the perennial growth zone (PZ). High-molecular weight carbon compounds accumulate there in cambium and cambium derivatives. Neither vernalization nor flowering were requirements for secondary growth and sequestration of storage compounds. The inflorescence zone with only primary growth, termed annual growth zone (AZ), or roots exhibited different storage characteristics. Following cytokinin application, cambium activity was enhanced and secondary phloem parenchyma was formed in the PZ and also in the AZ. In transcriptome analysis cytokinin-related genes represented enriched gene ontology terms and were expressed at higher level in PZ than AZ. Thus, A. alpina uses primarily the vegetative PZ for nutrient storage, coupled to cytokinin-promoted secondary growth. This finding lays a foundation for future studies addressing signals for perennial growth.
