3.5 Impact of drought stress on tapetum-specific expressed genes
To determine whether drought affected the development of the tapetum and
microspore at transcription level, 52 tapetum- and pollen- related
expressed genes were identified (Table S8). RNA-Seq data showed thatSolanum lycopersicum EXCESS MICROSPORES (SlEMS ),ABORTED MICROSPORES (SlAMS ), DEFECTIVE TAPETUM
DEVELOPMENT and FUNCTION1 (SlDTF1) DYSFUNCTIONAL TAPETUM1
(SlDYT1) and CALLOSE DEFECTIVE MICROSPORE1 (SlCDM1 ) were
markedly down-regulated whereas SlMYB80 was up-regulated under DS
condition at PMC-MEI stage. At TED-VUM stage, SlAMS , MALE
STERILITY1 (SlMS1 ) and ANTHER 7 (SlAT7) were
significantly drought-repressed (Figure 5). The up-regulation of at most
a gene at PMC-MEI stage while all examined genes were down-regulated at
TED-VUM stage is in line with the considerable amount of damage to the
tapetum and/or microspores caused by drought stress in anthers at
TED-VUM stage than at PMC-MEI stage as revealed by histo-cytological
analysis and suggest a dominant and positive role of SlMYB80 in drought
tolerance mechanism early in anther development.