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Two recent publications:

Murphy AF, Cating RA, Goyer A, Hamm PB, Rondon SI (2014) First report of natural infection by ‘Candidatus Liberibacter solanacearum’ in bittersweet nightshade (Solanum dulcamara) in the Columbia Basin of eastern Oregon. Plant Disease. 98: 1425.

Zallot R, Yazdani M, Goyer A, Ziemak MJ, Guan JC, McCarty DR, de Crécy-Lagard V, Gerdes S, Garrett TJ, Benach J, Hunt JF, Shintani DK and Hanson AD (2014) Salvage of the thiamin pyrimidine moiety by plant TenA proteins lacking an active-site cysteine. Biochemical Journal 463: 145-155.


The TenA protein family occurs in prokaryotes, plants and fungi; it has two subfamilies, one (TenA_C) having an active-site cysteine, the other (TenA_E) not. TenA_C proteins participate in thiamin salvage by hydrolysing the thiamin breakdown product amino-HMP (4-amino-5-aminomethyl-2-methylpyrimidine) to HMP (4-amino-5-hydroxymethyl-2-methylpyrimidine); the function of TenA_E proteins is unknown. Comparative analysis of prokaryote and plant genomes predicted that (i) TenA_E has a salvage role similar to, but not identical with, that of TenA_C and (ii) that TenA_E and TenA_C also have non-salvage roles since they occur in organisms that cannot make thiamin. Recombinant Arabidopsis and maize TenA_E proteins (At3g16990, GRMZM2G080501) hydrolysed amino-HMP to HMP and, far more actively, hydrolysed the N-formyl derivative of amino-HMP to amino-HMP. Ablating the At3g16990 gene in a line with a null mutation in the HMP biosynthesis gene ThiC prevented its rescue by amino-HMP. Ablating At3g16990 in the wild-type increased sensitivity to paraquat-induced oxidative stress; HMP overcame this increased sensitivity. Furthermore, the expression of TenA_E and ThiC genes in Arabidopsis and maize was inversely correlated. These results indicate that TenA_E proteins mediate amidohydrolase and aminohydrolase steps in the salvage of thiamin breakdown products. As such products can be toxic, TenA_E proteins may also pre-empt toxicity.

Aymerics' student, Bruce Robinson (CSS) was awarded a USDA-NIFA Western Sustainable Agriculture Research and Education grant, “Increasing the Marketability of Pacific Northwest Potatoes.”