PCR-GENERATED CDNA LIBRARY OF TRANSITION-STAGE MAIZE EMBRYOS - CLONING AND EXPRESSION OF CALMODULIN GENES DURING EARLY EMBRYOGENESIS

One hundred maize zygotic embryos microdissected at the transition sta ge were used to construct a cDNA library after non-selective PCR (NS-P CR) amplification of whole cDNA populations. The library contains 2.3 x 10(5) recombinants and two different calmodulin cDNAs were cloned us ing a heterologous probe from petunia. Calmodulin expression was confi rmed throughout maize embryogenesis at the mRNA, amplified cDNA and pr otein levels. Sequence analysis suggests a maize origin for both clone s and negligible nucleotide changes linked to PCR. This library is the first described for early plant embryos and represents a breakthrough to isolate genes involved in embryo differentiation.