Developmental impact on trans-acting dosage effects in maize aneuploids

The reduction in vigor or viability caused by aneuploidy may be the result of trans-acting dosage effects that reduce gene expression. To investigate the molecular and developmental parameters of aneuploid syndromes, the expr ession of sucrose synthase1 (sus1) and shrunken1 (sh1) was studied in 2-wee k-old plants. Expression of sus1 and sh1 was first investigated in euploids , where it was found that both transcripts varied in a diurnal fashion. Chr omosome arm number can be varied in a series from one to three doses in mai ze. In the 14 aneuploid dosage series examined, most caused changes in sus I and sh I RNA levels that were both gene and tissue specific. Results were compared to previous data from embryo and endosperm tissue. More dosage ef fects were detected and the magnitude of RNA level modulation was greater i n 2-week-old plant tissue. These findings suggest that the molecular conseq uences of aneuploidy might become more severe as development progresses. (C ) 2001 WiIey-Liss, Inc.