Transcriptome profiling reveals an IAA-regulated response to adventitious root formation in lotus seedling

Adventitious roots (ARs) of lotus (Nelumbonucifera Gaertn.) play a critical role in water and nutrient uptake. We found that exogenously applied 10-μM indole-3-acetic acid (IAA) promoted the formation of ARs, while 150-μM IAA significantly inhibited the emergence of ARs. However, little is known about these different responses to various concentrations of IAA at the molecular level. This study, therefore, examined the gene expression profiling in four libraries treated with 10- and 150-μM IAA based on the high-throughout tag sequencing technique. Approximately 2.4×107 clean tags were obtained after the removal of low-quality tags from each library respectively, among which about 10% clean tags were unambiguous tag-mapped genes to the reference genes. We found that some genes involved in auxin metabolism showed a similar tendency for expression in the A/CK and C/CK libraries, while three genes were enhanced their expression only in the A/CK libraries. Two transcription factors including B3 domain-containing protein At2g36080-like and trihelix transcription factor were up-regulated for transcriptional level in the A/C libraries. The expressions of six important genes related to AR formation were significantly different in the A/CK and C/CK libraries. In summary, this study provides a comprehensive understanding of gene expression regulated by IAA involved in AR formation in lotus.