Receptor-like cytoplasmic kinases (RLCKs) form a large family of proteins in plants. RLCKs have been found in different plant species, regulating plant immunity to different bacterial and fungal pathogens. Previous studies implicated <i>Arabidopsis</i> <i>botrytis induced kinase1 (BIK1)</i> and <i>tomato protein kinase 1b (TPK1b)</i> in plant resistance to <i>Pseudomonas syringae</i> and <i>Botrytis cinerea</i>. In this study, we classified 195 putative maize RLCKs into ten subfamilies. Based on the amino acid sequence similarity to BIK1 and TPK1b, a novel maize RLCK,<i> zea mays bik1-like kinase 1 (ZmBLK1)</i> was identified. Enzyme assays with cloned <i>ZmBLK1</i> revealed a functional kinase when expressed in planta. The recombinant protein located to the plasma membrane. Expression of <i>ZmBLK1</i> is highest in maize leaves compared to other structures at silking stage. Expression of the recombinant <i>ZmBLK1</i> significantly reduced the rate of lesion spread in maize leaves inoculated with the Goss’s wilt pathogen. In maize kernels, expression of <i>ZmBLK1</i> increases during kernel maturation. Kernels from transgenic maize overexpressing <i>ZmBLK1</i> were not resistant to <i>Aspergillus flavus</i> or to aflatoxin contamination. In addition, mutations were made in <i>ZmBLK1</i> that were hypothesized to create a constitutively active kinase. However, resulting proteins had similar activity to the wild-type ZmBLK1 and transgenic plants showed similar responses to the Goss’s wilt and Aspergillus ear rot pathogens. Overall, this research established the first characterization of RLCKs in maize and described a potential contribution of ZmBLK1 to maize immune responses.

Dynein is a minus end directed molecular motor required for numerous cellular processes during intracellular transport and mitosis. Pac1/LIS1 and Bik1/CLIP-170 are two proteins required for targeting dynein to cytoplasmic microtubule plus ends in budding yeast. The lab previously proposed a model whereby Pac1/LIS1 binds to the motor domain of dynein heavy chain, Dyn1/HC, forming a complex that interacts with the +TIP protein Bik1/CLIP170 at plus ends. This project focused on using Bimolecular Fluorescence Complementation (BiFC) to visualize protein-protein interactions among dynein pathway components in vivo. Budding yeast, Saccharomyces cerevisiae is an ideal system to manipulate dynein as it is a non-essential protein in this system. The BiFC assay fuses two non-fluorescent halves of Venus, a YFP-derivative, to proteins of interest. If an interaction between the proteins occur, the two halves are brought to close proximity and the fluorophore is reconstituted. Cells co-expressing Dyn1-VN with Pac1-VC or Bik1-VC exhibited fluorescent foci associated with microtubule plus ends, the cell cortex and spindle pole bodies (SPBs). Additionally, cells co-expressing Pac1-VC with Bik1-VN exhibited fluorescent foci associated with microtubule plus ends. Cells coexpressing Tub1-VC and Bik1-VN or Dyn1-VN have BiFC signal indicating that both interact with the microtubule directly. Pac-1 coexpressed with Tub1 had no signal above background. These data support that these three components associate at microtubule plus ends. Dyn1 and Pac1 interact with Bik1 at microtubule plus ends. Bik1 serves as a docking platform for the two, but dynein is still able to interact with microtubules, while Pac1 is not.