NaTrxh is an essential protein for pollen rejection in Nicotiana by increasing S‐RNase activity |
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Authors: | Maria D Torres‐Rodríguez Yuridia Cruz‐Zamora Javier A Jurez‐Díaz Brian Mooney Bruce A McClure Felipe Cruz‐García |
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Institution: | Maria D. Torres‐Rodríguez,Yuridia Cruz‐Zamora,Javier A. Juárez‐Díaz,Brian Mooney,Bruce A. McClure,Felipe Cruz‐García |
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Abstract: | In self‐incompatible Solanaceae, the pistil protein S‐RNase contributes to S‐specific pollen rejection in conspecific crosses, as well as to rejecting pollen from foreign species or whole clades. However, S‐RNase alone is not sufficient for either type of pollen rejection. We describe a thioredoxin (Trx) type h from Nicotiana alata, NaTrxh, which interacts with and reduces S‐RNase in vitro. Here, we show that expressing a redox‐inactive mutant, NaTrxhSS, suppresses both S‐specific pollen rejection and rejection of pollen from Nicotiana plumbaginifolia. Biochemical experiments provide evidence that NaTrxh specifically reduces the Cys155‐Cys185 disulphide bond of SC10‐Rnase, resulting in a significant increase of its ribonuclease activity. This reduction and increase in S‐RNase activity by NaTrxh helps to explain why S‐RNase alone could be insufficient for pollen rejection. |
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Keywords: | NaTrxh Nicotiana alata Self‐incompatibility S‐RNase |
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