SMALL AUXIN UP RNA62/75 Are Required for the Translation of Transcripts Essential for Pollen Tube Growth.

Successful pollen tube elongation is critical for double fertilization, but the biological functions of pollen tube genes and the regulatory machinery underlying this crucial process are largely unknown. A previous translatomic study revealed two Arabidopsis (Arabidopsis thaliana) SAUR (SMALL AUXIN UP RNA) genes, SAUR62 and SAUR75, whose expression is up-regulated by pollination. Here, we found that both SAUR62 and SAUR75 localized mainly to pollen tube nuclei. The siliques of homozygous saur62 (saur62/-), saur75 (saur75/-), and the SAUR62/75 RNA interference (RNAi) knockdown line had many aborted seeds. These lines had normal pollen viability but defective in vitro and in vivo pollen tube growth, with branching phenotypes. Immunoprecipitation with transgenic SAUR62/75-GFP flowers revealed ribosomal protein RPL12 family members as potential interacting partners, and their individual interactions were confirmed further by yeast two-hybrid and bimolecular fluorescence complementation assays. Polysome profiling showed reduced 80S ribosome abundance in homozygous saur62, saur75, ribosomal large subunit12c, and SAUR62/75 RNAi flowers, suggesting that SAUR62/75 play roles in ribosome assembly. To clarify their roles in translation, we analyzed total proteins from RNAi versus wild-type flowers by isobaric tags for relative and absolute quantitation, revealing significantly reduced expression of factors participating in pollen tube wall biogenesis and F-actin dynamics, which are critical for the elastic properties of tube elongation. Indeed, RNAi pollen tubes showed mislocalization of deesterified and esterified pectins and F-actin organization. Thus, the biological roles of SAUR62/75 and their RPL12 partners are critical in ribosomal pre-60S subunit assembly for efficient pollen tube elongation and subsequent fertilization.

Effects of Intentionally Treated Water on Growth of Arabidopsis thaliana Seeds with Cryptochrome Mutations.

OBJECTIVE: A previous experiment suggested that consumption of intentionally treated tea influenced subjective mood under double-blind, controlled conditions. To investigate that effect objectively, again under double-blind, controlled conditions, we studied whether Arabidopsis thaliana seeds hydrated with intentionally treated vs. untreated water would show differences in hypocotyl length, anthocyanin, and chlorophyll. DESIGN: Three Buddhist monks focused their intention on commercially bottled water with the goal of improving the growth of seeds; bottled water from the same source served as an untreated control. Seeds with the following three variations of cryptochrome (CRY) were used: the wild type Arabidopsis (Columbia-4), a gain-of-function mutation (His-CRY2), and a loss-of function mutation (cry1/2), where "gain" and "loss" refer to enhanced and reduced sensitivity to blue light, respectively. Seeds were hydrated with treated or untreated water under blinded conditions, and then placed in random positions in an incubator. The germination process was repeated three times in each experiment, each time using new seeds, and then the entire experiment was repeated four times. RESULTS: Data combined across the four experiments showed a significant decrease in hypocotyl length in the His-CRY2 seedlings (treated mean 1.31 ± 0.01mm, untreated mean 1.43 ± 0.01mm, P < 10-13), a significant increase in anthocyanin with all three forms of cry, particularly His-CRY2 (treated mean 17.0 ± 0.31mg, untreated mean 14.5 ± 0.31mg, P < 10-4), and a modest increase in chlorophyll in His-CRY2 (treated mean 247.6 ± 5.63mg, untreated mean 230.6 ± 5.63mg, P = .05). These outcomes conformed to the monks' intentions because a decrease in hypocotyl length and increase in anthocyanin and chlorophyll are associated with enhanced photomorphogenic growth. These experiments suggest that the His-CRY2 mutation of Arabidopsis may be an especially robust "detector" of intention.