Transgenic maize lines with cell-type specific expression of fluorescent proteins in plastids.
Plastid number and morphology vary dramatically between cell types and at different developmental stages. Furthermore, in C4 plants such as maize, chloroplast ultrastructure and biochemical functions are specialized in mesophyll and bundle sheath cells, which differentiate acropetally from the proplastid form in the leaf base. To develop visible markers for maize plastids, we have created a series of stable transgenics expressing fluorescent proteins fused to either the maize ubiquitin promoter, the mesophyll-specific phosphoenolpyruvate carboxylase (PepC) promoter, or the bundle sheath-specific Rubisco small subunit 1 (RbcS) promoter. Multiple independent events were examined and revealed that maize codon-optimized versions of YFP and GFP were particularly well expressed, and that expression was stably inherited. Plants carrying PepC promoter constructs exhibit YFP expression in mesophyll plastids and the RbcS promoter mediated expression in bundle sheath plastids. The PepC and RbcS promoter fusions also proved useful for identifying plastids in organs such as epidermis, silks, roots and trichomes. These tools will inform future plastid-related studies of wild-type and mutant maize plants and provide material from which different plastid types may be isolated.
Sattarzadeh
Amir
A
Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA.
Fuller
Jonathan
J
Moguel
Salvador
S
Wostrikoff
Katia
K
Sato
Shirley
S
Covshoff
Sarah
S
Clemente
Tom
T
Hanson
Maureen
M
Stern
David B
DB
D018506:Gene Expression Regulation, Plant; D008164:Luminescent Proteins / Q000235:genetics*; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D010730:Phosphoenolpyruvate Carboxylase / Q000235:genetics; D030821:Plants, Genetically Modified / Q000235:genetics; D018087:Plastids / Q000235:genetics*; D011401:Promoter Regions, Genetic; D012273:Ribulose-Bisphosphate Carboxylase / Q000235:genetics*; D003313:Zea mays / Q000235:genetics*
D008164:Luminescent Proteins; D010730:Phosphoenolpyruvate Carboxylase; D012273:Ribulose-Bisphosphate Carboxylase