Joji Grace Villamor

Max Planck Institute for Plant Breeding Research | MPIPZ · Department of Plant Microbe Interactions

Proline accumulation is one of the most prominent changes in plant metabolism during drought and low water potential; however, regulation and function of proline metabolism remain unclear. We used a combination of forward genetic screening based on a Proline Dehydrogenase1 (PDH1) promoter-luciferase reporter (PDH1pro:LUC2) and RNA sequencing of the...

Plants produce hundreds of glycosidases. Despite their importance in cell wall (re)-modelling, protein and lipid modification and metabolite conversion, very little is known of this large class of glycolytic enzymes, partly because of their post-translational regulation and their elusive substrates. Consequently, glycosidases are poorly defined in...

The herbicides glyphosate (Gly) and imazamox (Imx) inhibit the biosynthesis of aromatic and branched-chain amino acids, respectively. Although these herbicides inhibit different pathways, they have been reported to show several common physiological effects in their modes of action, such as increasing free amino acid contents and decreasing soluble...

Many protein activities are driven by ATP binding and hydrolysis. Here, we explore the ATP-binding proteome of the model plant Arabidopsis thaliana using Acyl-ATP (AcATP) probes. These probes target ATP binding sites and covalently label lysine residues in the ATP binding pocket. Gel-based profiling using biotinylated AcATP showed that labeling is...

Chemical probes have great potential for identifying functional residues in proteins in crude proteomes. Here we studied labeling sites of chemical probes based on sulfonyl fluorides (SFs) on plant and animal proteomes. Besides serine proteases and many other proteins, SF-based probes label Tyr residues in glutathione transferases (GSTs). The label...

The Arabidopsis thaliana accession Shahdara (Sha) differs from Landsberg erecta (Ler) and other accessions in its responses to drought and low water potential including lower levels of proline accumulation. However, Sha maintained greater seedling root elongation at low water potential and a higher NADP/NADPH ratio than Ler. Profiling of major amin...

Drought-induced proline accumulation is widely observed in plants but its regulation and adaptive value are not as well understood. Proline accumulation of the Arabidopsis accession Shakdara (Sha) was threefold less than that of Landsberg erecta (Ler) and quantitative trait loci mapping identified a reduced function allele of the proline synthesis...

To better define the still unclear role of proline (Pro) metabolism in drought resistance, we analyzed Arabidopsis (Arabidopsis thaliana) Δ(1)-pyrroline-5-carboxylate synthetase1 (p5cs1) mutants deficient in stress-induced Pro synthesis as well as proline dehydrogenase (pdh1) mutants blocked in Pro catabolism and found that both Pro synthesis and c...

Matrix metalloproteases (MMPs) are secreted or membrane-bound zinc-containing proteases that play diverse roles in development and immunity in plants and in tissue remodeling in animals. We developed a photoreactive probe based on the MMP inhibitor marimastat, conjugated to a 4-azidotetrafluorobenzoyl moiety as photoreactive group and biotin as det...

本研究透過順向遺傳學及逆向遺傳學研究策略，篩得一些T-DNA插入突變株。為了探討水稻轉錄因子APETALA2 (AP2) 基因的功能，利用逆向遺傳學的策略，篩得水稻T-DNA插入突變株M38333，其T-DNA插入水稻BAC OSJNBa0044E16第37,503 bp處，位於預測為AP2基因下游5,705 bp。M38333外表性狀與TNG67比較，呈現半矮性、開花延遲及在水稻劍葉lamina joint處傾斜下垂。分析T-DNA插入鄰近基因之表現，發現333-07 (unknown protein) 及333-09 (putative AP2 protein) 兩個基因有被活化大量表現，推測M38333的外表性狀特異可能藉由活化此兩基因所造成，目前正進一步構築大量表現此兩基因的水稻轉殖...

本研究透過順向遺傳學及逆向遺傳學研究策略，篩得一些T-DNA插入突變株。為了探討水稻轉錄因子APETALA2 (AP2) 基因的功能，利用逆向遺傳學的策略，篩得水稻T-DNA插入突變株M38333，其T-DNA插入水稻BAC OSJNBa0044E16第37,503 bp處，位於預測為AP2基因下游5,705 bp。M38333外表性狀與TNG67比較，呈現半矮性、開花延遲及在水稻劍葉lamina joint處傾斜下垂。分析T-DNA插入鄰近基因之表現，發現333-07 (unknown protein) 及333-09 (putative AP2 protein) 兩個基因有被活化大量表現，推測M38333的外表性狀特異可能藉由活化此兩基因所造成，目前正進一步構築大量表現此兩基因的水稻轉殖...