A reporter for noninvasively monitoring gene expression and plant transformation

Reporters have been widely used to visualize gene expression,protein localization,and other cellular activities,but the commonly used reporters require special equipment,expensive chemicals,or invasive treatments.Here,we construct a new reporter RUBY that converts tyrosine to vividly red betalain,which is clearly visible to naked eyes without the need of using special equipment or chemical treatments.We show that RUBY can be used to noninvasively monitor gene expression in plants.Furthermore,we show that RUBY is an effective selection marker for transformation events in both rice and Arabidopsis.The new reporter will be especially useful for monitoring cellular activities in large crop plants such as a fruit tree under field conditions and for observing transformation and gene expression in tissue culture under sterile conditions.

Anther Endothecium-Derived Very-Long-Chain Fatty Acids Facilitate Pollen Hydration in Arabidopsis

Dear Editor,Pollen hydration is a prerequisite for pollen germination and sub- sequent pollen tube growth. As a result of two decades of biochemical studies and genetic identification of the eceriferum （cer） male-sterile mutants, the very-long-chain fatty acid （VLCFA） lipids in the pollen coat have been well known to play a critical role in pollen hydration （Preuss et al., 1993; Fiebig et al., 2000; Hiscock and Allen, 2008）.

Phenylpropanoid Derivatives Are Essential Components of Sporopollenin in Vascular Plants

The outer wall of pollen and spores,namely the exine,is composed of sporopollenin,which is highly resistant to chemical reagents and enzymes.In this study,we demonstrated that phenylpropanoid pathway derivatives are essential components of sporopollenin in seed plants.Spectral analyses showed that the autofluorescence of Lilium and Arabidopsis sporopollenin is similar to that of lignin.Thioacidolysis and NMR analyses of pollen from Lilium and Cryptomeria further revealed that the sporopollenin of seed plants contains phenylpropanoid derivatives,including p-hydroxybenzoate(p-BA),p-coumarate(p-CA),ferulate(FA),and lignin guaiacyl(G)units.The phenylpropanoid pathway is expressed in the tapetum in Arabidopsis,consistent with the fact that the sporopollenin precursor originates from the tapetum.Further germination and comet assays showed that this pathway plays an important role in protection of pollen against UV radiation.In the pteridophyte plant species Ophioglossum vulgatum and Lycopodium clavata,phenylpropanoid derivatives including p-BA and p-CA were also detected,but G units were not.Taken together,our results indicate that phenylpropanoid derivatives are essential for sporopollenin synthesis in vascular plants.In addition,sporopollenin autofluorescence spectra of bryophytes,such as Physcomitrella and Haplocladium,exhibit distinct characteristics compared with those of vascular plants,indicating the diversity of sporopollenin among land plants.