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Incomplete transfer of accessory loci influencing S b MATE expression underlies genetic background effects for aluminum tolerance in sorghum
Author(s) -
Melo Janaina O.,
Lana Ubiraci G. P.,
Piñeros Miguel A.,
Alves Vera M. C.,
Guimarães Claudia T.,
Liu Jiping,
Zheng Yi,
Zhong Silin,
Fei Zhangjun,
Maron Lyza G.,
Schaffert Robert E.,
Kochian Leon V.,
Magalhaes Jurandir V.
Publication year - 2013
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.12029
Subject(s) - allele , biology , locus (genetics) , genetics , phenotype , gene , null allele
Summary Impaired root development caused by aluminum ( A l) toxicity is a major cause of grain yield reduction in crops cultivated on acid soils, which are widespread worldwide. In sorghum, the major A l‐tolerance locus, A lt SB , is due to the function of S b MATE , which is an A l‐activated root citrate transporter. Here we performed a molecular and physiological characterization of various A lt SB donors and near‐isogenic lines harboring various A lt SB alleles. We observed a partial transfer of A l tolerance from the parents to the near‐isogenic lines that was consistent across donor alleles, emphasizing the occurrence of strong genetic background effects related to A lt SB . This reduction in tolerance was variable, with a 20% reduction being observed when highly A l‐tolerant lines were the A lt SB donors, and a reduction as great as 70% when other A lt SB alleles were introgressed. This reduction in A l tolerance was closely correlated with a reduction in S b MATE expression in near‐isogenic lines, suggesting incomplete transfer of loci acting in trans on S b MATE . Nevertheless, A lt SB alleles from the highly A l‐tolerant sources SC 283 and SC 566 were found to retain high S b MATE expression, presumably via elements present within or near the A lt SB locus, resulting in significant transfer of the A l‐tolerance phenotype to the derived near‐isogenic lines. Allelic effects could not be explained by coding region polymorphisms, although occasional mutations may affect A l tolerance. Finally, we report on the extensive occurrence of alternative splicing for S b MATE , which may be an important component regulating S b MATE expression in sorghum by means of the nonsense‐mediated RNA decay pathway.