This review examines the role of ROS in in vitro recalcitrance and genetic transformation and the opportunities to improve transformation efficiency using antioxidants. Normally, the initial response of plants to pathogen attacks is an oxidative burst with rapid and transient production of reactive oxygen species ROS Wojtaszek
Yet despite enormous differences in their appearance, all plants have a similar underlying structure. This structure is derived from a reservoir of stem cells located at the growing tip, called the Shoot Apical Meristem SAM. The stem cells in the SAM continuously divide and replenish themselves, enabling the plant to grow throughout its life.
They also produce daughter cells that form organs such as leaves, stems and flowers. Precise regulation of stem cell activity is essential to balance tip growth with organ formation, and the ability to maintain a dynamic equilibrium of meristem cells is critical for plants to achieve their characteristic architecture.
Disruption of plant stem cell maintenance can cause dramatic effects including altered development, biomass accumulation and yield. The goal of research in the Fletcher Lab is to determine the molecular mechanisms that maintain Arabidopsis shoot and flower stem cell reservoirs, and to understand the early steps of organ formation.
Our approach involves a combination of genetics, molecular biology, cell biology and biochemistry.
Stem Cell Biology We are currently analyzing several plant stem cell maintenance pathways. The Arabidopsis CLAVATA3 CLV3 gene encodes a small-secreted polypeptide that is expressed in the shoot and floral stem cells and perceived by several receptor complexes at the surface of the underlying cells.
This regulatory pathway functions as a negative feedback loop that maintains a functional balance between stem cell accumulation and organ formation throughout the plant life cycle. ULT1 encodes a SAND domain putative transcriptional regulator that restricts stem cell accumulation and operates as a critical timing component of a pathway that terminates stem cell fate during flower formation.
We have demonstrated that ULT1 acts as a trithorax Group trxG factor that regulates the chromatin conformation of large numbers of target gene loci.
Our present goals are to further characterize the biochemical properties and downstream targets of ULT1 and the related ULT2 protein, and to identify additional components of the pathway.
Schematic of genes that regulate stem cell activity in the Arabidopsis shoot apical meristem Developmental Signaling We also use functional genomics to characterize members a plant-specific family of CLV3-related signaling molecules called CLE proteins and determine their roles in plant development.
Intercellular signaling pathways convey cell fate information, regulate cell division and differentiation processes, and propagate and amplify specific signaling states.
Yet members of only a few families of plant small signaling molecules have been studied and very little is known about how they coordinate growth and development. We have determined that most Arabidopsis tissues express multiple CLE genes in highly specific patterns, indicating that CLE-mediated signaling pathways are likely to play roles in many biological processes.
Our work has also demonstrated that, like CLV3, the CLE proteins function as secreted polypeptides that act in diverse intercellular signaling modules along with other WOX family members.
We are currently studying the roles of several CLE polypeptides in Arabidopsis shoot apical meristem function and leaf formation. Calpain-mediated positional information directs cell wall orientation to sustain plant stem cell activity, growth and development.
Plant and Cell Phys. Peptide signaling molecules in plant development. Annals of Botany Genetic and phenotypic analysis of shoot apical and floral meristem development. Regulation of Arabidopsis embryo and endosperm development by the polypeptide signaling molecule CLE8.
CLE polypeptide signaling gene expression in Arabidopsis embryos. Comprehensive analysis of CLE polypeptide signaling gene expression and over-expression activity in Arabidopsis.
Shoot apical meristem form and function. In Current Topics in Developmental Biology. Proper regulation of a sperm-specific cis-nat- siRNA is essential for double fertilization in Arabidopsis. Analyzing shoot apical meristem development.
In Methods in Plant Developmental Biology. Analyzing floral meristem development.The results of flow cytometry analysis of the cell cycle and EdU assays showed that, overexpression of circFGFR2 accelerated the proliferation of myoblast and QM-7 cells, whereas knockdown of circFGFR2 with siRNA reduced the proliferation of both cells.
From studying the morphology of plant cells and walls, organelles, and other cellular compartments all the way to more complex gene regulation and expression studies, cell and tissue analysis techniques and tools are critical not only for basic plant research but are also key for crop improvement programs.
For the plant transformation, we cultured only 50 ml Agrobacterium, which allowed all steps (precipitation and resuspension of Agrobacterium cells and floral dipping of Arabidopsis plants) to be carried out in single 50 ml Falcon tubes.
Jul 21, · LRL genes are part of an ancient gene-regulatory network that controls the development of tip-growing filamentous cells with rooting functions—rhizoids, caulonema, and root hairs—at the interface between land plants and the soil.
This auxin-regulated network was active early in land plant evolution and was present in the last common. Transcriptional Analysis of the Global Regulatory Networks Active in Pseudomonas syringae during Leaf Colonization Abstract The plant pathogenPseudomonas syringae pv.
syringae Ba grows and survives on leaf surfaces and in the leaf apoplast of its host, bean (Phaseolus vulgaris).To understand the contribution of distinct regulators to.
Analysis of published information indicates that the antioxidants used in plant transformation can be classified into two groups based on their biological function. resulting in plant cells.