β-expansins are divergently abundant in maize cultivars that contrast in their degree of salt resistance.

Zea mays L. exhibits a strong growth reduction in response to NaCl-induced stress that is attributable to a decline of cell division and elongation. Wall-loosening expansins are of major impact for cell wall extensibility and growth. This study provides an analysis of the impact of an 8-d 100 mM NaCl stress treatment on the mRNA abundance of the α-and β-expansin sub-families using real-time quantitative RT-PCR. Moreover, we provide a comparative study of plants that contrast in their degree of salt resistance in order to reveal contrasting features of physiological functions that may bear a causal relation to the differential response of plants to salt. In result, the transcript abundance of wall-loosening β-expansins was impaired in size-reduced leaves of the salt-sensitive hybrid but not in leaves of the salt-resistant hybrid that maintained growth. This indicates a role for the β-expansins in processes related to salt resistance.