Reduced expression of selected FASCICLIN-LIKE ARABINOGALACTAN PROTEIN genes associates with the abortion of kernels in field crops of Zea mays (maize) and of Arabidopsis seeds

DUMONT DE CHASSART, GONZALO JAVIER; RICARDI, MARTINIANO MARÍA; CAGNOLA, JUAN IGNACIO; ZHU, TONG; CHIMENTI, CLAUDIO; GHIGLIONE, HERNÁN; CASAL, JORGE JOSÉ; ESTEVEZ, JOSÉ MANUEL; IBARRA, SILVIA ELIZABETH; DELZER, BRENT; OTEGUI, MARÍA ELENA

PLANT, CELL AND ENVIRONMENT (PRINT)

WILEY-BLACKWELL PUBLISHING, INC

Año: 2018 vol. 41 p. 661 - 674

0140-7791

Abortion of fertilised ovaries at the tip of the ear can generate significant yield losses in maize crops. To investigate the mechanisms involved in this process, two maize hybrids were grown in field crops at two sowing densities and under three irrigation regimes (well-watered control, drought before pollination and drought during pollination), in all possible combinations. Samples of ear tips were taken 2-6 days after synchronous hand pollination and used for the analysis of gene expression and sugars. Glucose and fructose levels increased in kernels with high abortion risk. Several FASCICLIN-LIKE ARABINOGALACTAN PROTEIN (FLA) genes, showed negative correlation with abortion. The expression of ZmFLA7 responded to drought only at the tip of the ear. The abundance of arabinogalactan protein (AGP) glycan epitopes decreased with drought and pharmacological treatments that reduce AGP activity enhanced the abortion of fertilised ovaries. Drought also reduced the expression of AthFLA9 in the siliques of Arabidopsis thaliana. Gain- and loss-of-function mutants of Arabidopsis showed a negative correlation between AthFLA9 and seed abortion. Based on gene expression patterns, pharmacological and genetic evidence, we propose that stress-induced reductions in the expression of selected FLA genes enhance abortion of fertilised ovaries in maize and Arabidopsis.