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Sweet pepper's ferredoxin-like protein enhances resistance against two bacterial pathogens on Tomato (9-1-2007) |
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| Couple of months ago we have highlighted the findings of Teng-Yung Feng's group on the enhancing resistance against soft rot disease of a ferredoxin-like protein (Pflp) from sweet pepper on a variety of hosts: Oncidium orchid (Planta 217: 60-65 2003; Transgenic Res. 12: 329-336, 2003), tobacco (Physiol. Mol. Plant Path. 64: 103-110, 2004) and calla lilies (Plant Cell Report 26: 449-459, 2007). Now they demonstrated an enhancement of Pflp on the disease resistance of tomato against two bacterial pathogens (Ralstonia solanacearum and Erwinia carotovora subsp. carotovora). |
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| Welcome to the nanoworld of soil-plant interface (7-5-2007) |
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| Dynamic processes at the root-soil interface are of utmost importance for the performance of plants and are only at the beginning of being understood. The Rizosphere. Biochemistry and Organic Substances at the Soil-Plant interface (edited by R. Pinton, Z. Varanini and P. Nannipieri, 2007, CRC Press) gives an comprehensive overview on what is going on beneath the surface. A chapter on Nutrients as Regulators of Root morphology and Architecture by Wolfgang Schmidt (IPMB) and Bettina Linke (Humboldt University, Berlin) highlights recent progress in the understanding of how environmental signals affect the development and function of roots and how plants adapt to their ever changing environment. |
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| How the octad pollen of Cymbopetalum is formed? (5-12-2007) |
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| Compound pollen in the form of dyads, triads, tetrads, polyads, or pollinia has been reported from more than 56 families of angiosperms, but the precise way in which the grains are bound together is less well known. Our earlier study of tetrad pollen formation in Annona (Annonaceae) revealed that after meiosis the callose-cellulose envelope forms a special conjugation with individual microspores and the forthcoming callose digestion is incomplete. The undigested part forms a central binder holding the four microspores of the tetrad together. This process causes the microspores to rotate 180 degrees. Lately, we describe pollen formation in another annonaceous genus, Cymbopetalum, in which the pollen is shed in octads. In Cymbopetalum, two meiocytes, connected by abundant cytomictic channels, are produced in each sporangium. Octad pollen formation in Cymbopetalum is shown to be comparable to the synchronized formation of two connected Annona tetrads, which then integrate into a single octad. Unique features of Annona polyad formation, e.g. special binding between the callose-cellulose envelopes and microspores, incomplete callose digestion, and microspore rotation, also occur in Cymbopetalum. In addition, formation of the Cymbopetalum octad involves development of a cushion-like structure that binds the distal pronexine of all eight microspores, and there is the production of intine protrusions. This study is published in the January issue of Pl. Syst. Evol. 263: 13–23 (2007). |
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